<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:3d9a1754-2313-4ea7-9414-cad1912b49f5,g:a86cd31d-9404-456f-a41e-effca4d4b02f-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.federalrealty.com/role/CoverPage" xlink:type="simple" xlink:href="frt-20211231.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/CoverPage" xlink:type="extended" id="i3e32ca3c4ae748f89765c3696c36726d_CoverPage">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_2d205803-9443-4bb9-9182-be453d8ec9b4" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentType_2d205803-9443-4bb9-9182-be453d8ec9b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_538527de-4501-4035-8267-de17d8c416a8" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentAnnualReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentAnnualReport_538527de-4501-4035-8267-de17d8c416a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_f55ff7c6-26a2-4fc4-9bb0-9cd8780f0307" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentPeriodEndDate_f55ff7c6-26a2-4fc4-9bb0-9cd8780f0307" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_27f78369-c448-45d6-b9b2-2858cd974222" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_CurrentFiscalYearEndDate_27f78369-c448-45d6-b9b2-2858cd974222" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_ac3ad9fb-7e83-484f-9141-810a59720354" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentTransitionReport_ac3ad9fb-7e83-484f-9141-810a59720354" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_150d0a1c-48df-44c2-9a96-4488a4df375c" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityFileNumber_150d0a1c-48df-44c2-9a96-4488a4df375c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_77d7b1a3-8e2c-4f25-bdf9-05f1f58d3188" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityRegistrantName_77d7b1a3-8e2c-4f25-bdf9-05f1f58d3188" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_66761655-fbfe-4a9c-837e-1005e7ae7307" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityIncorporationStateCountryCode_66761655-fbfe-4a9c-837e-1005e7ae7307" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_c888ed4b-ac30-43e5-85aa-7a4e52b50676" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityTaxIdentificationNumber_c888ed4b-ac30-43e5-85aa-7a4e52b50676" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_54fb67ad-3cb6-45a6-be4b-f481aca0e211" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityAddressAddressLine1_54fb67ad-3cb6-45a6-be4b-f481aca0e211" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_d79224ef-6b85-46f5-82e6-1402b6a5de16" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityAddressCityOrTown_d79224ef-6b85-46f5-82e6-1402b6a5de16" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_82df1965-591a-4b95-96fb-c9a9d77900ad" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityAddressStateOrProvince_82df1965-591a-4b95-96fb-c9a9d77900ad" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_27a9256b-d4e1-43d2-82bc-367cff4f571d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityAddressPostalZipCode_27a9256b-d4e1-43d2-82bc-367cff4f571d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_460f40f8-7f84-4665-8f10-a4853f554dca" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_CityAreaCode_460f40f8-7f84-4665-8f10-a4853f554dca" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_4a43b3cd-7a8f-4cd4-aacf-eac6430f094e" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_LocalPhoneNumber_4a43b3cd-7a8f-4cd4-aacf-eac6430f094e" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_b3da6a6e-5454-4e87-addd-be1a23973f8e" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_Security12bTitle_b3da6a6e-5454-4e87-addd-be1a23973f8e" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_8cba07bd-3352-401f-867e-cea3bcadc8d1" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_TradingSymbol_8cba07bd-3352-401f-867e-cea3bcadc8d1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_bdb43a2a-471b-4592-9ae9-38fc1fef3ba6" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_SecurityExchangeName_bdb43a2a-471b-4592-9ae9-38fc1fef3ba6" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_1d645e4d-8045-40a7-8564-2c817892b799" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_1d645e4d-8045-40a7-8564-2c817892b799" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_610fa62f-3b5a-431f-8828-1acddc6b2c0f" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityVoluntaryFilers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityVoluntaryFilers_610fa62f-3b5a-431f-8828-1acddc6b2c0f" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_7c756d89-aa41-42f6-8181-2c665d9d2e98" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityCurrentReportingStatus_7c756d89-aa41-42f6-8181-2c665d9d2e98" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_45a757c3-4aaa-4a9e-9584-70617199fa00" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityInteractiveDataCurrent_45a757c3-4aaa-4a9e-9584-70617199fa00" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_11a58557-25e0-4799-a387-d67884339861" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityFilerCategory_11a58557-25e0-4799-a387-d67884339861" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_2f1ded24-7027-4d15-9354-01a3766aede3" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntitySmallBusiness_2f1ded24-7027-4d15-9354-01a3766aede3" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_1a5e85ac-9ca1-4ad7-b620-1be215a05482" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityEmergingGrowthCompany_1a5e85ac-9ca1-4ad7-b620-1be215a05482" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_f1a14970-5096-4a4f-be65-7711c379e7cf" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_IcfrAuditorAttestationFlag_f1a14970-5096-4a4f-be65-7711c379e7cf" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_a023dd49-a0cc-4cee-986b-3e9ea21dbb14" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityShellCompany_a023dd49-a0cc-4cee-986b-3e9ea21dbb14" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_5683380e-61ef-47d5-b182-1711d91ae5f5" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityPublicFloat"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityPublicFloat_5683380e-61ef-47d5-b182-1711d91ae5f5" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_033bafaf-65e5-4176-adc1-959144f12c82" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_033bafaf-65e5-4176-adc1-959144f12c82" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_27ce7093-8fe5-43af-a14d-0193c82594b6" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntityCentralIndexKey_27ce7093-8fe5-43af-a14d-0193c82594b6" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_6374dd75-2142-4f19-a38e-0e1555b6a1bf" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentFiscalYearFocus_6374dd75-2142-4f19-a38e-0e1555b6a1bf" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_aac4f028-0cd1-4d20-a717-fddb9cbdc39f" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_DocumentFiscalPeriodFocus_aac4f028-0cd1-4d20-a717-fddb9cbdc39f" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_ccf71da1-f3c8-47f2-97f9-9cd81954b43d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_AmendmentFlag_ccf71da1-f3c8-47f2-97f9-9cd81954b43d" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_NoTradingSymbolFlag_fb9df1c6-8e2b-4117-bff6-4bbfc4255d6e" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_NoTradingSymbolFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_NoTradingSymbolFlag_fb9df1c6-8e2b-4117-bff6-4bbfc4255d6e" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_e1f09ae9-77d3-46cf-91d7-38703c2cc464" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_c3ec1904-7697-4ecb-b7a8-bde823560438" xlink:to="loc_dei_EntitiesTable_e1f09ae9-77d3-46cf-91d7-38703c2cc464" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_75b73a67-f7e9-43e1-8586-0b30e395a9c9" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_e1f09ae9-77d3-46cf-91d7-38703c2cc464" xlink:to="loc_dei_EntityListingsExchangeAxis_75b73a67-f7e9-43e1-8586-0b30e395a9c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_75b73a67-f7e9-43e1-8586-0b30e395a9c9_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_75b73a67-f7e9-43e1-8586-0b30e395a9c9" xlink:to="loc_dei_ExchangeDomain_75b73a67-f7e9-43e1-8586-0b30e395a9c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_bb3e7c0c-a224-462b-9b38-be91315f25bf" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_75b73a67-f7e9-43e1-8586-0b30e395a9c9" xlink:to="loc_dei_ExchangeDomain_bb3e7c0c-a224-462b-9b38-be91315f25bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_7db9a24d-9a73-4f71-b8f3-4e7077376b2f" xlink:href="https://xbrl.sec.gov/exch/2021/exch-2021.xsd#exch_XNYS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_bb3e7c0c-a224-462b-9b38-be91315f25bf" xlink:to="loc_exch_XNYS_7db9a24d-9a73-4f71-b8f3-4e7077376b2f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_67481888-965d-4226-a0f1-fbcd638bcfbf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_e1f09ae9-77d3-46cf-91d7-38703c2cc464" xlink:to="loc_us-gaap_StatementClassOfStockAxis_67481888-965d-4226-a0f1-fbcd638bcfbf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_67481888-965d-4226-a0f1-fbcd638bcfbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_67481888-965d-4226-a0f1-fbcd638bcfbf" xlink:to="loc_us-gaap_ClassOfStockDomain_67481888-965d-4226-a0f1-fbcd638bcfbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_f14a54d9-b86d-49f5-b135-1ed5aac5a82e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_67481888-965d-4226-a0f1-fbcd638bcfbf" xlink:to="loc_us-gaap_ClassOfStockDomain_f14a54d9-b86d-49f5-b135-1ed5aac5a82e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonSharesOfBeneficialInterestMember_930e515e-bf88-4c5a-8898-378734ecd52e" xlink:href="frt-20211231.xsd#frt_CommonSharesOfBeneficialInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f14a54d9-b86d-49f5-b135-1ed5aac5a82e" xlink:to="loc_frt_CommonSharesOfBeneficialInterestMember_930e515e-bf88-4c5a-8898-378734ecd52e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DepositorySharesMember_6d67d999-03e1-4d90-b75c-6e74b44542e0" xlink:href="frt-20211231.xsd#frt_DepositorySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f14a54d9-b86d-49f5-b135-1ed5aac5a82e" xlink:to="loc_frt_DepositorySharesMember_6d67d999-03e1-4d90-b75c-6e74b44542e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_dbf49229-f37e-4863-9f8d-d1f0f07d4a11" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_e1f09ae9-77d3-46cf-91d7-38703c2cc464" xlink:to="loc_dei_LegalEntityAxis_dbf49229-f37e-4863-9f8d-d1f0f07d4a11" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_dbf49229-f37e-4863-9f8d-d1f0f07d4a11_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_dbf49229-f37e-4863-9f8d-d1f0f07d4a11" xlink:to="loc_dei_EntityDomain_dbf49229-f37e-4863-9f8d-d1f0f07d4a11_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_4021aade-ea90-4f8a-a13b-e3ae0cf8f610" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_dbf49229-f37e-4863-9f8d-d1f0f07d4a11" xlink:to="loc_dei_EntityDomain_4021aade-ea90-4f8a-a13b-e3ae0cf8f610" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FederalRealtyOPLPMember_d6eaf886-d310-4263-83b5-b87942b04884" xlink:href="frt-20211231.xsd#frt_FederalRealtyOPLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_4021aade-ea90-4f8a-a13b-e3ae0cf8f610" xlink:to="loc_frt_FederalRealtyOPLPMember_d6eaf886-d310-4263-83b5-b87942b04884" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="frt-20211231.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedBalanceSheets" xlink:type="extended" id="i8102457035714fcdb5a6db5cb45715f7_ConsolidatedBalanceSheets">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RentalProperties_d81c1588-4398-40d7-a903-4fb1220af825" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RentalProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_RentalProperties_d81c1588-4398-40d7-a903-4fb1220af825" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressGross_6c180405-0e10-4274-8ff9-cdfa2de7de06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_ConstructionInProgressGross_6c180405-0e10-4274-8ff9-cdfa2de7de06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost_1d80aa33-9c21-4e06-a97f-8253c7d5c91c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAtCost_1d80aa33-9c21-4e06-a97f-8253c7d5c91c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_8a83fb7f-5c71-44ac-87e8-dee8b559b706" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_8a83fb7f-5c71-44ac-87e8-dee8b559b706" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_f2947e87-20cb-4fa8-ae97-90f7c04c7f43" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_f2947e87-20cb-4fa8-ae97-90f7c04c7f43" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2d30700e-7531-4c82-abd5-5163eebf0d5b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2d30700e-7531-4c82-abd5-5163eebf0d5b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndNotesReceivableNet_59b994f7-019e-4fb9-b5b8-5c282c1f4e09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsAndNotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_AccountsAndNotesReceivableNet_59b994f7-019e-4fb9-b5b8-5c282c1f4e09" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_e90b0d70-826e-44a8-b830-67281d999b63" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_e90b0d70-826e-44a8-b830-67281d999b63" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_9714b185-2873-4dce-a83b-7ec9428699c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_9714b185-2873-4dce-a83b-7ec9428699c3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_b6e8b97f-79af-403d-a406-8fc6f3eca7ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_b6e8b97f-79af-403d-a406-8fc6f3eca7ce" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset_155e30c7-4d1c-4aa7-ae57-7d0358a11b67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAsset_155e30c7-4d1c-4aa7-ae57-7d0358a11b67" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssets_0605377e-69c6-46e3-ac3e-389cc6c2f8b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssets_0605377e-69c6-46e3-ac3e-389cc6c2f8b7" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_7ef88b4d-b5fb-4ea1-a029-e719e34569a9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1e3e9a05-81a2-4412-a777-ae70bc46f1bd" xlink:to="loc_us-gaap_Assets_7ef88b4d-b5fb-4ea1-a029-e719e34569a9" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_75eece10-55e8-4fe9-8d23-c1b82ea1105b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_SecuredDebt_75eece10-55e8-4fe9-8d23-c1b82ea1105b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayable_d6cbc9ca-c18e-4649-bb09-cc16bd634de5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_NotesPayable_d6cbc9ca-c18e-4649-bb09-cc16bd634de5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebt_17f3fc5a-67d0-442b-9075-580334ec0d60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnsecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_UnsecuredDebt_17f3fc5a-67d0-442b-9075-580334ec0d60" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_c3fd6ab1-b770-41f0-bf2c-a60a62de54ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_c3fd6ab1-b770-41f0-bf2c-a60a62de54ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_f8cc38d7-a384-421c-8fe8-351e8acc5167" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_f8cc38d7-a384-421c-8fe8-351e8acc5167" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDepositLiability_f9cf2ec7-1725-4e6c-a3ff-1884938bc50d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecurityDepositLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_SecurityDepositLiability_f9cf2ec7-1725-4e6c-a3ff-1884938bc50d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_7571badc-92ee-41b4-9ecb-7bb396b90061" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_OperatingLeaseLiability_7571badc-92ee-41b4-9ecb-7bb396b90061" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_4875eb9a-cfd5-4e46-8178-eb7c8d316496" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_FinanceLeaseLiability_4875eb9a-cfd5-4e46-8178-eb7c8d316496" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCreditsAndOtherLiabilities_bcc6f8a9-6af4-42db-b37f-63997ade1c55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCreditsAndOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_DeferredCreditsAndOtherLiabilities_bcc6f8a9-6af4-42db-b37f-63997ade1c55" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_14f9f70a-13f6-4b70-ba28-f4d4675ab8e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_c97d7101-77a3-48b6-a27a-bd19d3d52cf5" xlink:to="loc_us-gaap_Liabilities_14f9f70a-13f6-4b70-ba28-f4d4675ab8e0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_137bba8b-bc9f-464e-8635-14e871197c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_CommitmentsAndContingencies_137bba8b-bc9f-464e-8635-14e871197c8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_dccd4c54-a0e7-460c-b9d1-2680a0210976" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_dccd4c54-a0e7-460c-b9d1-2680a0210976" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_7843ce8e-e099-403e-a564-78e69fe652d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_PreferredStockValue_7843ce8e-e099-403e-a564-78e69fe652d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_2f17b1e1-9fae-4c93-8a0d-5d2bc914fc02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_CommonStockValue_2f17b1e1-9fae-4c93-8a0d-5d2bc914fc02" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_69b5fd02-daa3-4209-9944-07b534275e40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_69b5fd02-daa3-4209-9944-07b534275e40" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_d2982455-bf72-4b0b-b3ee-ec6b743f7f68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_d2982455-bf72-4b0b-b3ee-ec6b743f7f68" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_7eef15f8-c34a-4411-8869-d8202d4ad1ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_7eef15f8-c34a-4411-8869-d8202d4ad1ee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_0c05daa3-dab6-4fa6-a0fc-ecf0b9a7ec9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_StockholdersEquity_0c05daa3-dab6-4fa6-a0fc-ecf0b9a7ec9d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_64028a0c-fe39-4f73-bb5c-ad05dfbdaf97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_MinorityInterest_64028a0c-fe39-4f73-bb5c-ad05dfbdaf97" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a37386-a78a-43f9-b9ae-5808b3494805" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_21bb492e-ca59-41d5-bdb5-713a080b459d" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a37386-a78a-43f9-b9ae-5808b3494805" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_8986920c-f3a7-44c2-881a-55d45fe2fb9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_8986920c-f3a7-44c2-881a-55d45fe2fb9d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_16b3fbee-bb16-4e04-b939-af96732f3bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_49018a31-a84c-43af-8b02-d834eb4d058f" xlink:to="loc_us-gaap_StatementTable_16b3fbee-bb16-4e04-b939-af96732f3bc1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4c142a1a-8f21-4319-8ade-969c240c1c29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_16b3fbee-bb16-4e04-b939-af96732f3bc1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4c142a1a-8f21-4319-8ade-969c240c1c29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_4c142a1a-8f21-4319-8ade-969c240c1c29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4c142a1a-8f21-4319-8ade-969c240c1c29" xlink:to="loc_us-gaap_ClassOfStockDomain_4c142a1a-8f21-4319-8ade-969c240c1c29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_4da54ab4-2f10-48b6-8b2e-547a148054f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4c142a1a-8f21-4319-8ade-969c240c1c29" xlink:to="loc_us-gaap_ClassOfStockDomain_4da54ab4-2f10-48b6-8b2e-547a148054f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_d48c2f00-69ce-4464-b50a-69c38279f788" xlink:href="frt-20211231.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4da54ab4-2f10-48b6-8b2e-547a148054f4" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_d48c2f00-69ce-4464-b50a-69c38279f788" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_0d16aa7d-d9be-4d8b-96c8-bce62cb9915c" xlink:href="frt-20211231.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4da54ab4-2f10-48b6-8b2e-547a148054f4" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_0d16aa7d-d9be-4d8b-96c8-bce62cb9915c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedBalanceSheetsParentheticals" xlink:type="simple" xlink:href="frt-20211231.xsd#ConsolidatedBalanceSheetsParentheticals"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedBalanceSheetsParentheticals" xlink:type="extended" id="id0607df217784102b86c6b0368d42b45_ConsolidatedBalanceSheetsParentheticals">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OperatingRealEstateFromConsolidatedVariableInterestEntities_14a135a5-b69a-472d-a804-0094e42f0ac5" xlink:href="frt-20211231.xsd#frt_OperatingRealEstateFromConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_frt_OperatingRealEstateFromConsolidatedVariableInterestEntities_14a135a5-b69a-472d-a804-0094e42f0ac5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Constructioninprogresofconsolidatedvariableieestentity_b0971b4b-6009-4052-bb2d-12c5d7a8060c" xlink:href="frt-20211231.xsd#frt_Constructioninprogresofconsolidatedvariableieestentity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_frt_Constructioninprogresofconsolidatedvariableieestentity_b0971b4b-6009-4052-bb2d-12c5d7a8060c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities_981def83-77a1-466d-86f8-ee803fcc110d" xlink:href="frt-20211231.xsd#frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities_981def83-77a1-466d-86f8-ee803fcc110d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_11e9f26e-2d8d-4a37-a1bc-33c5b69d233d" xlink:href="frt-20211231.xsd#frt_MortgagePayableFromConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_11e9f26e-2d8d-4a37-a1bc-33c5b69d233d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_3f12f0fd-76c1-474d-b845-9c35e1acabac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_3f12f0fd-76c1-474d-b845-9c35e1acabac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_95dd545e-bf8d-4871-a8ea-82bb165d5c63" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_95dd545e-bf8d-4871-a8ea-82bb165d5c63" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_22dbbf65-596f-4468-b629-e71146304a0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_22dbbf65-596f-4468-b629-e71146304a0a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_55c81529-e6d9-45a7-af0e-98afc954ae09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockLiquidationPreference_55c81529-e6d9-45a7-af0e-98afc954ae09" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_126ecf22-c45e-4035-9427-ea863a836cc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockSharesIssued_126ecf22-c45e-4035-9427-ea863a836cc2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_7cf1fdf5-1588-4b52-9798-6b607fa325cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_7cf1fdf5-1588-4b52-9798-6b607fa325cf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_b1a48c26-406a-47fc-9265-fc95124597cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_b1a48c26-406a-47fc-9265-fc95124597cc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_1eeda15a-4007-433e-a6d8-8711fec29378" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_1eeda15a-4007-433e-a6d8-8711fec29378" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_84a6f961-e328-4f34-ad4e-4b435b6c8b87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_CommonStockSharesIssued_84a6f961-e328-4f34-ad4e-4b435b6c8b87" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_59717d95-68c5-4744-9b49-8bc12bff26ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_59717d95-68c5-4744-9b49-8bc12bff26ab" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_dcee83c8-fa64-4ddc-8a6c-8bfd36556951" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_68bce761-6e26-4dbc-b6d2-e799ae21158e" xlink:to="loc_us-gaap_StatementTable_dcee83c8-fa64-4ddc-8a6c-8bfd36556951" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_ff3fe86f-25b7-4641-a2d2-187e1946712a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_dcee83c8-fa64-4ddc-8a6c-8bfd36556951" xlink:to="loc_us-gaap_StatementClassOfStockAxis_ff3fe86f-25b7-4641-a2d2-187e1946712a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ff3fe86f-25b7-4641-a2d2-187e1946712a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ff3fe86f-25b7-4641-a2d2-187e1946712a" xlink:to="loc_us-gaap_ClassOfStockDomain_ff3fe86f-25b7-4641-a2d2-187e1946712a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_fe095685-8ae3-4cae-8882-aeb4646cca00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ff3fe86f-25b7-4641-a2d2-187e1946712a" xlink:to="loc_us-gaap_ClassOfStockDomain_fe095685-8ae3-4cae-8882-aeb4646cca00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_eabaaca4-e1a6-48cb-82cc-0f42faddd4e3" xlink:href="frt-20211231.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_fe095685-8ae3-4cae-8882-aeb4646cca00" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_eabaaca4-e1a6-48cb-82cc-0f42faddd4e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_9ea68d80-3111-433a-b40e-d0d6866e1ae3" xlink:href="frt-20211231.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_fe095685-8ae3-4cae-8882-aeb4646cca00" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_9ea68d80-3111-433a-b40e-d0d6866e1ae3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementOfShareholdersEquity" xlink:type="simple" xlink:href="frt-20211231.xsd#ConsolidatedStatementOfShareholdersEquity"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementOfShareholdersEquity" xlink:type="extended" id="ie2dd91dcee414df9aeb72a5f1ed92e14_ConsolidatedStatementOfShareholdersEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_52c908e2-f718-4968-881a-52b1fb659fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_52c908e2-f718-4968-881a-52b1fb659fbd" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_79b6c22c-25d4-4599-8ba8-a21394f7d80f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_SharesOutstanding_79b6c22c-25d4-4599-8ba8-a21394f7d80f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_5fdbb19c-35a3-403f-9efc-6bdaa1d33d6e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_5fdbb19c-35a3-403f-9efc-6bdaa1d33d6e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AdoptionOfNewAccountingStandard_42866779-7138-43df-a86f-2971a44da4a4" xlink:href="frt-20211231.xsd#frt_AdoptionOfNewAccountingStandard"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_AdoptionOfNewAccountingStandard_42866779-7138-43df-a86f-2971a44da4a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ProfitLossExcludingRedeemableNoncontrollingInterests_e9949344-ae14-4ce9-b9a3-c5d0fb8c6d7b" xlink:href="frt-20211231.xsd#frt_ProfitLossExcludingRedeemableNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_ProfitLossExcludingRedeemableNoncontrollingInterests_e9949344-ae14-4ce9-b9a3-c5d0fb8c6d7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_88a9a1c0-4ac1-4815-b247-852b91a00068" xlink:href="frt-20211231.xsd#frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_88a9a1c0-4ac1-4815-b247-852b91a00068" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_60a16c0a-fb03-416e-b13d-7ea8a433df52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_60a16c0a-fb03-416e-b13d-7ea8a433df52" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_80c2770b-4c8d-4f71-a425-45c13e26a270" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_DividendsCommonStockCash_80c2770b-4c8d-4f71-a425-45c13e26a270" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStockCash_38b7b956-6b90-41e8-893c-a045bfd93464" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPreferredStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_DividendsPreferredStockCash_38b7b956-6b90-41e8-893c-a045bfd93464" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_1d8bddb2-372b-4317-9331-63e3d98cd515" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_1d8bddb2-372b-4317-9331-63e3d98cd515" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_0dc31889-c60e-413d-8525-bca863fff57c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_0dc31889-c60e-413d-8525-bca863fff57c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_8fc1c03e-7537-4e76-b71b-6f01430a872d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_8fc1c03e-7537-4e76-b71b-6f01430a872d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_cde779e2-ed0f-43b7-a4f6-37d5f4dca84c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_cde779e2-ed0f-43b7-a4f6-37d5f4dca84c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan_f5236d9e-4358-404a-a467-a5043755193b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan_f5236d9e-4358-404a-a467-a5043755193b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareBasedCompensationExpenseNetShares_38712a0d-514f-4c10-9c54-1e7395c0fb8b" xlink:href="frt-20211231.xsd#frt_ShareBasedCompensationExpenseNetShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_ShareBasedCompensationExpenseNetShares_38712a0d-514f-4c10-9c54-1e7395c0fb8b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareBasedCompensationExpenseNetValue_71a6bae6-ef5d-4aa5-b47d-eee2351d525c" xlink:href="frt-20211231.xsd#frt_ShareBasedCompensationExpenseNetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_ShareBasedCompensationExpenseNetValue_71a6bae6-ef5d-4aa5-b47d-eee2351d525c" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_7f04f799-6376-421c-861d-aaebd1bfce35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_7f04f799-6376-421c-861d-aaebd1bfce35" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_ea275c8b-55e1-4d8f-9ab6-4116c05cd49c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_ea275c8b-55e1-4d8f-9ab6-4116c05cd49c" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConversionAndRedemptionOfOperatingPartnershipUnitsInShares_d9b32184-44df-49d1-8575-b25d61a65c0e" xlink:href="frt-20211231.xsd#frt_ConversionAndRedemptionOfOperatingPartnershipUnitsInShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_ConversionAndRedemptionOfOperatingPartnershipUnitsInShares_d9b32184-44df-49d1-8575-b25d61a65c0e" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConversionAndRedemptionOfOperatingPartnershipUnits_f33268b1-8ea3-4249-b887-1b5ed1216520" xlink:href="frt-20211231.xsd#frt_ConversionAndRedemptionOfOperatingPartnershipUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_ConversionAndRedemptionOfOperatingPartnershipUnits_f33268b1-8ea3-4249-b887-1b5ed1216520" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Contributionsfromnoncontrollinginterests_1a1c138f-2361-40ba-a4cf-595529df2248" xlink:href="frt-20211231.xsd#frt_Contributionsfromnoncontrollinginterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_frt_Contributionsfromnoncontrollinginterests_1a1c138f-2361-40ba-a4cf-595529df2248" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_ac5ea72a-34e7-4d51-b423-8e6d058fcaf7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_ac5ea72a-34e7-4d51-b423-8e6d058fcaf7" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_75acec25-f74c-4425-8d1d-dd12cc60cd76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_24fa4e0f-2083-4b49-9e2a-182de7665ed5" xlink:to="loc_us-gaap_StockholdersEquityOther_75acec25-f74c-4425-8d1d-dd12cc60cd76" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_9a78c802-7fa9-440b-be73-155f0d0113b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_22138092-9f37-4a3b-a9d8-d0283742dd9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_329f4406-41b8-4387-98f1-bd30e944facc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_52c908e2-f718-4968-881a-52b1fb659fbd" xlink:to="loc_us-gaap_StatementTable_329f4406-41b8-4387-98f1-bd30e944facc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_ad5bf77e-d5b1-4593-bac2-d2b714d0df63" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_329f4406-41b8-4387-98f1-bd30e944facc" xlink:to="loc_us-gaap_StatementClassOfStockAxis_ad5bf77e-d5b1-4593-bac2-d2b714d0df63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ad5bf77e-d5b1-4593-bac2-d2b714d0df63_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ad5bf77e-d5b1-4593-bac2-d2b714d0df63" xlink:to="loc_us-gaap_ClassOfStockDomain_ad5bf77e-d5b1-4593-bac2-d2b714d0df63_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_d3760be3-8bb8-4560-8135-d9623712f11e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ad5bf77e-d5b1-4593-bac2-d2b714d0df63" xlink:to="loc_us-gaap_ClassOfStockDomain_d3760be3-8bb8-4560-8135-d9623712f11e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_451db8f5-4d33-4a2d-9846-78d921f7238d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_d3760be3-8bb8-4560-8135-d9623712f11e" xlink:to="loc_us-gaap_CommonStockMember_451db8f5-4d33-4a2d-9846-78d921f7238d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_5aee59ad-4840-4d78-b2f7-8213f769eebe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_d3760be3-8bb8-4560-8135-d9623712f11e" xlink:to="loc_us-gaap_PreferredStockMember_5aee59ad-4840-4d78-b2f7-8213f769eebe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_bd4fa7d5-fa61-4abc-ba7c-380b77945550" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_329f4406-41b8-4387-98f1-bd30e944facc" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_bd4fa7d5-fa61-4abc-ba7c-380b77945550" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_bd4fa7d5-fa61-4abc-ba7c-380b77945550_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_bd4fa7d5-fa61-4abc-ba7c-380b77945550" xlink:to="loc_us-gaap_EquityComponentDomain_bd4fa7d5-fa61-4abc-ba7c-380b77945550_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_bd4fa7d5-fa61-4abc-ba7c-380b77945550" xlink:to="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_e39d44ee-afa5-4046-9a20-fe97e88f69ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_PreferredStockMember_e39d44ee-afa5-4046-9a20-fe97e88f69ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_ae70c3af-d2e1-4813-a6d1-76e824242c0d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_CommonStockMember_ae70c3af-d2e1-4813-a6d1-76e824242c0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_1b380fe8-127e-40f6-879f-372ac932ecdd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_1b380fe8-127e-40f6-879f-372ac932ecdd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_1e046fe8-58ea-4b4a-bb1b-1c5c9d366ac8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_1e046fe8-58ea-4b4a-bb1b-1c5c9d366ac8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2d858035-7b53-4e93-90f8-354d98894f9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2d858035-7b53-4e93-90f8-354d98894f9c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_032bf460-d924-4f58-a3d8-27f402d9e176" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0acb7f08-da2e-4002-bce9-276e03fa6ae1" xlink:to="loc_us-gaap_NoncontrollingInterestMember_032bf460-d924-4f58-a3d8-27f402d9e176" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesRealEstateDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesRealEstateDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesRealEstateDetails" xlink:type="extended" id="i1060a580795d4003a8f620e9c525971f_SummaryOfSignificantAccountingPoliciesRealEstateDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_bd27f179-de14-4830-ad16-8ac22e732403" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_39f73b56-b8a1-4160-94ad-7267537c455e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_bd27f179-de14-4830-ad16-8ac22e732403" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_39f73b56-b8a1-4160-94ad-7267537c455e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DepreciationExpenseRealEstate_ac264982-0cc6-4580-9c84-618bbcc52199" xlink:href="frt-20211231.xsd#frt_DepreciationExpenseRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_bd27f179-de14-4830-ad16-8ac22e732403" xlink:to="loc_frt_DepreciationExpenseRealEstate_ac264982-0cc6-4580-9c84-618bbcc52199" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c62b9792-ab6b-445a-8338-dd5ba6034bf1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_bd27f179-de14-4830-ad16-8ac22e732403" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c62b9792-ab6b-445a-8338-dd5ba6034bf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c62b9792-ab6b-445a-8338-dd5ba6034bf1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2583fff7-6801-4530-a98d-0ede47de8dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2b6a78cf-cc6e-468c-99f3-18d6657ebbb1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2583fff7-6801-4530-a98d-0ede47de8dd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_1077f087-d1bf-4dc0-b54a-e4aaf02d0ed3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2583fff7-6801-4530-a98d-0ede47de8dd8" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_1077f087-d1bf-4dc0-b54a-e4aaf02d0ed3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MinorImprovementsFurnitureAndEquipmentMember_076785af-78b4-44d4-b3a4-0a363c45811b" xlink:href="frt-20211231.xsd#frt_MinorImprovementsFurnitureAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2583fff7-6801-4530-a98d-0ede47de8dd8" xlink:to="loc_frt_MinorImprovementsFurnitureAndEquipmentMember_076785af-78b4-44d4-b3a4-0a363c45811b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_8b565af9-1138-40e0-95ed-d367fc6bd296" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c62b9792-ab6b-445a-8338-dd5ba6034bf1" xlink:to="loc_srt_RangeAxis_8b565af9-1138-40e0-95ed-d367fc6bd296" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8b565af9-1138-40e0-95ed-d367fc6bd296_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8b565af9-1138-40e0-95ed-d367fc6bd296" xlink:to="loc_srt_RangeMember_8b565af9-1138-40e0-95ed-d367fc6bd296_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_86d52fdc-5910-478a-ad16-9ee617fbb1c4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8b565af9-1138-40e0-95ed-d367fc6bd296" xlink:to="loc_srt_RangeMember_86d52fdc-5910-478a-ad16-9ee617fbb1c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_37aa212e-5f47-4401-a886-59b2c48dfbd3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_86d52fdc-5910-478a-ad16-9ee617fbb1c4" xlink:to="loc_srt_MinimumMember_37aa212e-5f47-4401-a886-59b2c48dfbd3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_56c71422-2397-4d17-80c9-9d1969b1f8e0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_86d52fdc-5910-478a-ad16-9ee617fbb1c4" xlink:to="loc_srt_MaximumMember_56c71422-2397-4d17-80c9-9d1969b1f8e0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesPrepaidExpensesandOtherAssetsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesPrepaidExpensesandOtherAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesPrepaidExpensesandOtherAssetsDetails" xlink:type="extended" id="i5bf54b2851d04d10960016366b3dec17_SummaryOfSignificantAccountingPoliciesPrepaidExpensesandOtherAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_frt_PrepaidExpensesAndOtherAssetsLineItems_433bd725-d291-46d0-8ea4-8a846d1da72f" xlink:href="frt-20211231.xsd#frt_PrepaidExpensesAndOtherAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CapitalizedLeaseCostsAmortizationRange_e13ebd38-da41-4c45-947d-c0ad871dac2e" xlink:href="frt-20211231.xsd#frt_CapitalizedLeaseCostsAmortizationRange"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_PrepaidExpensesAndOtherAssetsLineItems_433bd725-d291-46d0-8ea4-8a846d1da72f" xlink:to="loc_frt_CapitalizedLeaseCostsAmortizationRange_e13ebd38-da41-4c45-947d-c0ad871dac2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PrepaidExpensesAndOtherAssetsTable_aedeffd3-9418-491d-9068-2d081cebcde9" xlink:href="frt-20211231.xsd#frt_PrepaidExpensesAndOtherAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_frt_PrepaidExpensesAndOtherAssetsLineItems_433bd725-d291-46d0-8ea4-8a846d1da72f" xlink:to="loc_frt_PrepaidExpensesAndOtherAssetsTable_aedeffd3-9418-491d-9068-2d081cebcde9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frt_PrepaidExpensesAndOtherAssetsTable_aedeffd3-9418-491d-9068-2d081cebcde9" xlink:to="loc_srt_RangeAxis_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9" xlink:to="loc_srt_RangeMember_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1d5e2ecb-11cd-4d7a-b29e-51f035f719ce" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c1e2ca13-3f2d-4bfa-b9ca-ac86724b01a9" xlink:to="loc_srt_RangeMember_1d5e2ecb-11cd-4d7a-b29e-51f035f719ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_26fb10b0-ecf0-4302-adff-7850ed42d2f1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1d5e2ecb-11cd-4d7a-b29e-51f035f719ce" xlink:to="loc_srt_MinimumMember_26fb10b0-ecf0-4302-adff-7850ed42d2f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_0f71bb16-4598-4b76-b793-c58f99acd831" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1d5e2ecb-11cd-4d7a-b29e-51f035f719ce" xlink:to="loc_srt_MaximumMember_0f71bb16-4598-4b76-b793-c58f99acd831" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesDerivativeInstrumentsandMortgageNotesReceivableDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesDerivativeInstrumentsandMortgageNotesReceivableDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesDerivativeInstrumentsandMortgageNotesReceivableDetails" xlink:type="extended" id="if31f48714d3241318b3a7a3c05e762ee_SummaryOfSignificantAccountingPoliciesDerivativeInstrumentsandMortgageNotesReceivableDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_8cf67b14-7e7f-4944-afa3-580e38a097b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfInterestRateDerivativesHeld_d53da7c4-50e2-4a5d-bafc-b5a4f4bf0099" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfInterestRateDerivativesHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_8cf67b14-7e7f-4944-afa3-580e38a097b4" xlink:to="loc_us-gaap_NumberOfInterestRateDerivativesHeld_d53da7c4-50e2-4a5d-bafc-b5a4f4bf0099" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_4fa43bfa-e680-4bdb-ad8c-8a952f9f9672" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_8cf67b14-7e7f-4944-afa3-580e38a097b4" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_4fa43bfa-e680-4bdb-ad8c-8a952f9f9672" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_8cf67b14-7e7f-4944-afa3-580e38a097b4" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_44e07d09-78c7-4c14-aae9-e81b20f6cda2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:to="loc_us-gaap_DebtInstrumentAxis_44e07d09-78c7-4c14-aae9-e81b20f6cda2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_44e07d09-78c7-4c14-aae9-e81b20f6cda2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_44e07d09-78c7-4c14-aae9-e81b20f6cda2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_44e07d09-78c7-4c14-aae9-e81b20f6cda2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_87d539cd-e984-45c9-8fcf-2744dffb7919" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_44e07d09-78c7-4c14-aae9-e81b20f6cda2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_87d539cd-e984-45c9-8fcf-2744dffb7919" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_f0914f6d-716b-40cc-8314-61c13800e28b" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_87d539cd-e984-45c9-8fcf-2744dffb7919" xlink:to="loc_frt_HobokenMember_f0914f6d-716b-40cc-8314-61c13800e28b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_fba20ec6-568b-43e4-af9d-5e9a930c0755" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_fba20ec6-568b-43e4-af9d-5e9a930c0755" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_fba20ec6-568b-43e4-af9d-5e9a930c0755_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fba20ec6-568b-43e4-af9d-5e9a930c0755" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_fba20ec6-568b-43e4-af9d-5e9a930c0755_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_17cb4efb-a6b9-4305-bbeb-0d1cd2ded587" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fba20ec6-568b-43e4-af9d-5e9a930c0755" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_17cb4efb-a6b9-4305-bbeb-0d1cd2ded587" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_9a281683-e769-4ffa-9211-c3c16bd54a03" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_17cb4efb-a6b9-4305-bbeb-0d1cd2ded587" xlink:to="loc_us-gaap_SecuredDebtMember_9a281683-e769-4ffa-9211-c3c16bd54a03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_a237d068-8490-4861-abb5-c1bb46288f69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_a237d068-8490-4861-abb5-c1bb46288f69" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_a237d068-8490-4861-abb5-c1bb46288f69_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_a237d068-8490-4861-abb5-c1bb46288f69" xlink:to="loc_us-gaap_RelatedPartyDomain_a237d068-8490-4861-abb5-c1bb46288f69_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e6c6c3ae-f926-467a-b9f7-d516332784dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_a237d068-8490-4861-abb5-c1bb46288f69" xlink:to="loc_us-gaap_RelatedPartyDomain_e6c6c3ae-f926-467a-b9f7-d516332784dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_2081c921-6d97-4a11-abf2-6406a73c4a52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_e6c6c3ae-f926-467a-b9f7-d516332784dd" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_2081c921-6d97-4a11-abf2-6406a73c4a52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3b9a7349-7764-409d-a691-fd82b8ece6e9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c74faa1a-8ff1-4224-bcfb-e7183cb1ea15" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3b9a7349-7764-409d-a691-fd82b8ece6e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenProvidentMember_6d2b6e40-d8e0-4cf0-bb17-0be3433740e1" xlink:href="frt-20211231.xsd#frt_HobokenProvidentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3b9a7349-7764-409d-a691-fd82b8ece6e9" xlink:to="loc_frt_HobokenProvidentMember_6d2b6e40-d8e0-4cf0-bb17-0be3433740e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AssemblyRowHotelMember_a7257d7d-88f7-4833-8b3a-abfa71aa2c64" xlink:href="frt-20211231.xsd#frt_AssemblyRowHotelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3b9a7349-7764-409d-a691-fd82b8ece6e9" xlink:to="loc_frt_AssemblyRowHotelMember_a7257d7d-88f7-4833-8b3a-abfa71aa2c64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_ec31c0d0-82f6-4f6d-96ae-2659a777ab20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_7096c934-a781-41ea-85ad-589a619d206e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_ec31c0d0-82f6-4f6d-96ae-2659a777ab20" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ec31c0d0-82f6-4f6d-96ae-2659a777ab20_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ec31c0d0-82f6-4f6d-96ae-2659a777ab20" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ec31c0d0-82f6-4f6d-96ae-2659a777ab20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5229bd4e-72ef-403f-8296-a5ea7495c897" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ec31c0d0-82f6-4f6d-96ae-2659a777ab20" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5229bd4e-72ef-403f-8296-a5ea7495c897" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNumberOfLoans_7a0ddb7c-7cc4-4b00-888c-6bdb271159c6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateNumberOfLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_srt_MortgageLoansOnRealEstateNumberOfLoans_7a0ddb7c-7cc4-4b00-888c-6bdb271159c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_d8ef5911-9505-4ce8-97e6-28e465140ce1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_us-gaap_NotesReceivableNet_d8ef5911-9505-4ce8-97e6-28e465140ce1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WeightedAverageInterestRateonFinancingReceivable_525f967a-f534-4998-9a25-63381bd7e65c" xlink:href="frt-20211231.xsd#frt_WeightedAverageInterestRateonFinancingReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_frt_WeightedAverageInterestRateonFinancingReceivable_525f967a-f534-4998-9a25-63381bd7e65c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetProceedsFromRepaymentOfMortgageNotesReceivable_f5985c8d-192b-4891-afa1-16d28085a4ba" xlink:href="frt-20211231.xsd#frt_NetProceedsFromRepaymentOfMortgageNotesReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_frt_NetProceedsFromRepaymentOfMortgageNotesReceivable_f5985c8d-192b-4891-afa1-16d28085a4ba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DecreaseInMortgageNotesReceivableNetValuationAllowance_bfd60b52-02b0-403a-98b6-79232d50542a" xlink:href="frt-20211231.xsd#frt_DecreaseInMortgageNotesReceivableNetValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_frt_DecreaseInMortgageNotesReceivableNetValuationAllowance_bfd60b52-02b0-403a-98b6-79232d50542a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_32a32c27-1afb-44f4-81fe-1b801aaacad4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_de786b3e-987f-478f-8d8a-65eba3c0d13e" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_32a32c27-1afb-44f4-81fe-1b801aaacad4" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_01fb87b5-7114-4c09-a207-72468bacc939" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_32a32c27-1afb-44f4-81fe-1b801aaacad4" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_01fb87b5-7114-4c09-a207-72468bacc939" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_01fb87b5-7114-4c09-a207-72468bacc939_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_01fb87b5-7114-4c09-a207-72468bacc939" xlink:to="loc_us-gaap_ReceivableTypeDomain_01fb87b5-7114-4c09-a207-72468bacc939_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_11b51568-f277-48e8-a71c-b65b6116143b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_01fb87b5-7114-4c09-a207-72468bacc939" xlink:to="loc_us-gaap_ReceivableTypeDomain_11b51568-f277-48e8-a71c-b65b6116143b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesVariableInterestEntitiesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesVariableInterestEntitiesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesVariableInterestEntitiesDetails" xlink:type="extended" id="i5050586225754bf28f9694eef8571485_SummaryOfSignificantAccountingPoliciesVariableInterestEntitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_aca10bb0-c239-498e-ac27-a1e86fe651bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_aca10bb0-c239-498e-ac27-a1e86fe651bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NumberofConsolidatedVariableInterestEntities_5896e839-e335-4e29-9d4c-19b035712f53" xlink:href="frt-20211231.xsd#frt_NumberofConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:to="loc_frt_NumberofConsolidatedVariableInterestEntities_5896e839-e335-4e29-9d4c-19b035712f53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_VariableInterestEntityNetRealEstateAssets_17179f88-b5ea-4a12-99ac-b0c0253431cc" xlink:href="frt-20211231.xsd#frt_VariableInterestEntityNetRealEstateAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:to="loc_frt_VariableInterestEntityNetRealEstateAssets_17179f88-b5ea-4a12-99ac-b0c0253431cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_33cb9977-5535-4e49-b9d5-a69f73636a8b" xlink:href="frt-20211231.xsd#frt_MortgagePayableFromConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:to="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_33cb9977-5535-4e49-b9d5-a69f73636a8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_10983488-760b-497e-b5cc-3b52db4aa814" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_e1543599-321b-4542-bfcc-da19d6401754" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_10983488-760b-497e-b5cc-3b52db4aa814" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesAxis_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_10983488-760b-497e-b5cc-3b52db4aa814" xlink:to="loc_us-gaap_RealEstatePropertiesAxis_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesDomain_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RealEstatePropertiesAxis_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc" xlink:to="loc_us-gaap_RealEstatePropertiesDomain_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesDomain_91de54ea-17a3-4a5f-9192-aaa8aca3d089" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RealEstatePropertiesAxis_9921a3c7-8ec1-412e-9c71-efc3e63d3fdc" xlink:to="loc_us-gaap_RealEstatePropertiesDomain_91de54ea-17a3-4a5f-9192-aaa8aca3d089" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnconsolidatedPropertiesMember_4561ab2d-4cb4-47b3-8f84-9b2ee121ade9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnconsolidatedPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_91de54ea-17a3-4a5f-9192-aaa8aca3d089" xlink:to="loc_us-gaap_UnconsolidatedPropertiesMember_4561ab2d-4cb4-47b3-8f84-9b2ee121ade9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_dc2604e0-c0c5-4799-a8b9-cad072924ed5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_10983488-760b-497e-b5cc-3b52db4aa814" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_dc2604e0-c0c5-4799-a8b9-cad072924ed5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_dc2604e0-c0c5-4799-a8b9-cad072924ed5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_dc2604e0-c0c5-4799-a8b9-cad072924ed5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_dc2604e0-c0c5-4799-a8b9-cad072924ed5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_bee0c16a-faee-4030-ba14-b02957da3f6c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_dc2604e0-c0c5-4799-a8b9-cad072924ed5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_bee0c16a-faee-4030-ba14-b02957da3f6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LaAlamedaAssemblyRowHotelMember_52bb9f41-1f71-48a8-acde-7121783f5ed4" xlink:href="frt-20211231.xsd#frt_LaAlamedaAssemblyRowHotelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_bee0c16a-faee-4030-ba14-b02957da3f6c" xlink:to="loc_frt_LaAlamedaAssemblyRowHotelMember_52bb9f41-1f71-48a8-acde-7121783f5ed4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseHotelJVMember_bf9cf67a-e513-4d25-b523-5d19846b638d" xlink:href="frt-20211231.xsd#frt_PikeRoseHotelJVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_bee0c16a-faee-4030-ba14-b02957da3f6c" xlink:to="loc_frt_PikeRoseHotelJVMember_bf9cf67a-e513-4d25-b523-5d19846b638d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesLeaseInformationDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesLeaseInformationDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesLeaseInformationDetails" xlink:type="extended" id="i046a9bb1d84d48bda3dc78c845458e21_SummaryOfSignificantAccountingPoliciesLeaseInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_759853ea-4641-4447-8fc2-c46bb25011d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Cumulativeimpacttoaccumulateddividendsinexcessofnetincome_d8799a68-8353-4d2c-a596-76a966214500" xlink:href="frt-20211231.xsd#frt_Cumulativeimpacttoaccumulateddividendsinexcessofnetincome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_759853ea-4641-4447-8fc2-c46bb25011d8" xlink:to="loc_frt_Cumulativeimpacttoaccumulateddividendsinexcessofnetincome_d8799a68-8353-4d2c-a596-76a966214500" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_c64baa0d-fb11-4fd0-8a83-a4cf13c30d7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_759853ea-4641-4447-8fc2-c46bb25011d8" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_c64baa0d-fb11-4fd0-8a83-a4cf13c30d7e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_41f2db3c-302d-4f49-adb1-a5ed428278cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_c64baa0d-fb11-4fd0-8a83-a4cf13c30d7e" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_41f2db3c-302d-4f49-adb1-a5ed428278cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_41f2db3c-302d-4f49-adb1-a5ed428278cb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_41f2db3c-302d-4f49-adb1-a5ed428278cb" xlink:to="loc_us-gaap_TypeOfAdoptionMember_41f2db3c-302d-4f49-adb1-a5ed428278cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_5421f6ad-3eda-4345-abb2-23506b3d749e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_41f2db3c-302d-4f49-adb1-a5ed428278cb" xlink:to="loc_us-gaap_TypeOfAdoptionMember_5421f6ad-3eda-4345-abb2-23506b3d749e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_51f66723-6015-40c4-86d7-6d1785ca0ec5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_5421f6ad-3eda-4345-abb2-23506b3d749e" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_51f66723-6015-40c4-86d7-6d1785ca0ec5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesIncomeTaxesSegmentsandForwardEquitySalesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesIncomeTaxesSegmentsandForwardEquitySalesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesIncomeTaxesSegmentsandForwardEquitySalesDetails" xlink:type="extended" id="i50a417cf683a4a5c91dd2e8f3bd31219_SummaryOfSignificantAccountingPoliciesIncomeTaxesSegmentsandForwardEquitySalesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_213a8fde-b2e8-4c1b-8d45-3bd7decabe92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AggregateOfferingPriceOfCommonShare_9be8a7b9-5c8f-4650-a88e-3f1a69e2f148" xlink:href="frt-20211231.xsd#frt_AggregateOfferingPriceOfCommonShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_213a8fde-b2e8-4c1b-8d45-3bd7decabe92" xlink:to="loc_frt_AggregateOfferingPriceOfCommonShare_9be8a7b9-5c8f-4650-a88e-3f1a69e2f148" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_1758c344-182f-418b-a156-2e9a3b52b554" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_213a8fde-b2e8-4c1b-8d45-3bd7decabe92" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_1758c344-182f-418b-a156-2e9a3b52b554" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_14565dc5-4b47-4aea-8577-998d647473fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1758c344-182f-418b-a156-2e9a3b52b554" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_14565dc5-4b47-4aea-8577-998d647473fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_14565dc5-4b47-4aea-8577-998d647473fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_14565dc5-4b47-4aea-8577-998d647473fd" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_14565dc5-4b47-4aea-8577-998d647473fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_d6b75eec-ae90-4a26-911a-9454ca16826c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_14565dc5-4b47-4aea-8577-998d647473fd" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_d6b75eec-ae90-4a26-911a-9454ca16826c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AtMarketEquityProgramMember_d34999ec-01d4-426c-a36b-d434fabffce8" xlink:href="frt-20211231.xsd#frt_AtMarketEquityProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_d6b75eec-ae90-4a26-911a-9454ca16826c" xlink:to="loc_frt_AtMarketEquityProgramMember_d34999ec-01d4-426c-a36b-d434fabffce8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesSupplementalCashFlowDisclosuresDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SummaryOfSignificantAccountingPoliciesSupplementalCashFlowDisclosuresDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesSupplementalCashFlowDisclosuresDetails" xlink:type="extended" id="ice395629ad9a4639b74556173c2834f4_SummaryOfSignificantAccountingPoliciesSupplementalCashFlowDisclosuresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasedAssetsLineItems_c7403d3d-ea72-4429-b62e-8dab2333b508" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_53174b12-8fa1-4559-baeb-27a7349e5257" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfOperatingLeasedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_c7403d3d-ea72-4429-b62e-8dab2333b508" xlink:to="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_53174b12-8fa1-4559-baeb-27a7349e5257" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_918c358f-2e8e-437a-8fa2-bc417f4552e2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_53174b12-8fa1-4559-baeb-27a7349e5257" xlink:to="loc_srt_RangeAxis_918c358f-2e8e-437a-8fa2-bc417f4552e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_918c358f-2e8e-437a-8fa2-bc417f4552e2_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_918c358f-2e8e-437a-8fa2-bc417f4552e2" xlink:to="loc_srt_RangeMember_918c358f-2e8e-437a-8fa2-bc417f4552e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9122fc0c-3a15-4f74-997a-525ee2ac531e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_918c358f-2e8e-437a-8fa2-bc417f4552e2" xlink:to="loc_srt_RangeMember_9122fc0c-3a15-4f74-997a-525ee2ac531e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_eb3e4677-432b-4077-9358-30b33d671db0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9122fc0c-3a15-4f74-997a-525ee2ac531e" xlink:to="loc_srt_MinimumMember_eb3e4677-432b-4077-9358-30b33d671db0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_55e2744c-e942-44b6-9acb-001147676590" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9122fc0c-3a15-4f74-997a-525ee2ac531e" xlink:to="loc_srt_MaximumMember_55e2744c-e942-44b6-9acb-001147676590" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_b201d5de-7296-401b-9087-5ee664364d4d" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsByPropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_53174b12-8fa1-4559-baeb-27a7349e5257" xlink:to="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_b201d5de-7296-401b-9087-5ee664364d4d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsPropertyTypeDomain_b201d5de-7296-401b-9087-5ee664364d4d_default" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsPropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_b201d5de-7296-401b-9087-5ee664364d4d" xlink:to="loc_frt_RealEstateInvestmentsPropertyTypeDomain_b201d5de-7296-401b-9087-5ee664364d4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsPropertyTypeDomain_1a951975-3094-4864-983a-cd2f0fea3111" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsPropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_b201d5de-7296-401b-9087-5ee664364d4d" xlink:to="loc_frt_RealEstateInvestmentsPropertyTypeDomain_1a951975-3094-4864-983a-cd2f0fea3111" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/RealEstate2021PropertyAcquisitionsandDispositionsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#RealEstate2021PropertyAcquisitionsandDispositionsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/RealEstate2021PropertyAcquisitionsandDispositionsDetails" xlink:type="extended" id="ic314cb8f7a794eb6bb49ab22ed3616da_RealEstate2021PropertyAcquisitionsandDispositionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OwnershipInterestOfPartnerInOurJointVenture_04a0fb55-0b2d-4da7-9804-cea594be834e" xlink:href="frt-20211231.xsd#frt_OwnershipInterestOfPartnerInOurJointVenture"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_OwnershipInterestOfPartnerInOurJointVenture_04a0fb55-0b2d-4da7-9804-cea594be834e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_033d3e8a-ceae-4e7d-8e43-2013a2ad707f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_033d3e8a-ceae-4e7d-8e43-2013a2ad707f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt_260914d5-0fa1-45e8-b62b-4f2fb7bf105f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_RepaymentsOfSecuredDebt_260914d5-0fa1-45e8-b62b-4f2fb7bf105f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GainOnAcquisitionOfControllingInterest_81a746e7-4219-4917-bba7-82755e9d0508" xlink:href="frt-20211231.xsd#frt_GainOnAcquisitionOfControllingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_GainOnAcquisitionOfControllingInterest_81a746e7-4219-4917-bba7-82755e9d0508" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PurchasePriceOfFeeInterestInRealEstate_e26530a3-1a1e-4228-8752-a72ed8f119ad" xlink:href="frt-20211231.xsd#frt_PurchasePriceOfFeeInterestInRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_PurchasePriceOfFeeInterestInRealEstate_e26530a3-1a1e-4228-8752-a72ed8f119ad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DecreaseInOperatingLeaseRightOfUseAssets_bd53c17a-3953-42a1-abec-6ff013576fcf" xlink:href="frt-20211231.xsd#frt_DecreaseInOperatingLeaseRightOfUseAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_DecreaseInOperatingLeaseRightOfUseAssets_bd53c17a-3953-42a1-abec-6ff013576fcf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_d609059e-0bc8-4a1b-9e55-aa20270eb6be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_d609059e-0bc8-4a1b-9e55-aa20270eb6be" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_8b306d6c-8b94-42b1-979f-c870d8d63336" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_8b306d6c-8b94-42b1-979f-c870d8d63336" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ControllingInterestPercent_14245d07-d9f6-4a8d-b545-77f084b06c02" xlink:href="frt-20211231.xsd#frt_ControllingInterestPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_ControllingInterestPercent_14245d07-d9f6-4a8d-b545-77f084b06c02" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrossValueofRealEstate_451728fb-ca83-46b8-b60f-1bf53a39c068" xlink:href="frt-20211231.xsd#frt_GrossValueofRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_GrossValueofRealEstate_451728fb-ca83-46b8-b60f-1bf53a39c068" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AcquiredLeaseCosts_946d7883-769e-4aeb-980b-11ecab5fb5e3" xlink:href="frt-20211231.xsd#frt_AcquiredLeaseCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_AcquiredLeaseCosts_946d7883-769e-4aeb-980b-11ecab5fb5e3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_c4a5b972-0d06-44b9-bc2d-94b8b57113d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_c4a5b972-0d06-44b9-bc2d-94b8b57113d9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAcquired_33387ce7-5fca-46af-98ed-02ebf85140e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_BelowMarketLeaseAcquired_33387ce7-5fca-46af-98ed-02ebf85140e7" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_1747a062-a30a-4a7a-8912-1c507952b18c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_1747a062-a30a-4a7a-8912-1c507952b18c" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AboveMarketLiability_a0362bb2-5ef8-4a05-920b-dd16d629139a" xlink:href="frt-20211231.xsd#frt_AboveMarketLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_frt_AboveMarketLiability_a0362bb2-5ef8-4a05-920b-dd16d629139a" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_0f17b245-479f-433c-a227-e158b1f32016" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_OperatingLeaseLiability_0f17b245-479f-433c-a227-e158b1f32016" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfRealEstate_cb5f4a74-0f4b-4cdc-a753-f6122226a92c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_ProceedsFromSaleOfRealEstate_cb5f4a74-0f4b-4cdc-a753-f6122226a92c" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_b3a10a09-2c79-465b-a9ba-3fe675b977b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_b3a10a09-2c79-465b-a9ba-3fe675b977b5" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2503079f-cccf-4d3d-98f8-8a06ca83c20d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9c6af616-d526-46e6-bc78-0567164a0fca" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2503079f-cccf-4d3d-98f8-8a06ca83c20d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_70f8e521-73b7-4801-a438-30b256ac5388" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2503079f-cccf-4d3d-98f8-8a06ca83c20d" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_70f8e521-73b7-4801-a438-30b256ac5388" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_70f8e521-73b7-4801-a438-30b256ac5388_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_70f8e521-73b7-4801-a438-30b256ac5388" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_70f8e521-73b7-4801-a438-30b256ac5388_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_70f8e521-73b7-4801-a438-30b256ac5388" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseHotelJVMember_41f85e19-fae4-4b2f-96de-ae137a49e2e3" xlink:href="frt-20211231.xsd#frt_PikeRoseHotelJVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_PikeRoseHotelJVMember_41f85e19-fae4-4b2f-96de-ae137a49e2e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MountVernonMember_3272750d-e19c-44bc-bfa2-fe37a725e172" xlink:href="frt-20211231.xsd#frt_MountVernonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_MountVernonMember_3272750d-e19c-44bc-bfa2-fe37a725e172" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ChesterbrookMember_71d27464-b8bb-4a64-875c-b0441f55c88a" xlink:href="frt-20211231.xsd#frt_ChesterbrookMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_ChesterbrookMember_71d27464-b8bb-4a64-875c-b0441f55c88a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrossmontCenterMember_a728f0df-d1fe-42db-a783-984a96a90123" xlink:href="frt-20211231.xsd#frt_GrossmontCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_GrossmontCenterMember_a728f0df-d1fe-42db-a783-984a96a90123" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CamelbackColonnadeMember_cc337cae-b88d-45c2-9450-d513d03d60bc" xlink:href="frt-20211231.xsd#frt_CamelbackColonnadeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_CamelbackColonnadeMember_cc337cae-b88d-45c2-9450-d513d03d60bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HiltonVillageMember_a1e3f30d-a7b3-4bb2-a09f-2de4b23658ae" xlink:href="frt-20211231.xsd#frt_HiltonVillageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_HiltonVillageMember_a1e3f30d-a7b3-4bb2-a09f-2de4b23658ae" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TwinbrookeShoppingCentreMember_4c0f7a89-fd74-4baf-a333-fa0377b94a11" xlink:href="frt-20211231.xsd#frt_TwinbrookeShoppingCentreMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_TwinbrookeShoppingCentreMember_4c0f7a89-fd74-4baf-a333-fa0377b94a11" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TwoProperties2021Member_d95f3cb8-59b4-402d-ba92-d5ee9bfbfc13" xlink:href="frt-20211231.xsd#frt_TwoProperties2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8bbee9de-b568-4cbc-a771-87cf8cd68f54" xlink:to="loc_frt_TwoProperties2021Member_d95f3cb8-59b4-402d-ba92-d5ee9bfbfc13" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_de78c1fd-00f5-46d0-b123-52940c376ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2503079f-cccf-4d3d-98f8-8a06ca83c20d" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_de78c1fd-00f5-46d0-b123-52940c376ce8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_de78c1fd-00f5-46d0-b123-52940c376ce8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_de78c1fd-00f5-46d0-b123-52940c376ce8" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_de78c1fd-00f5-46d0-b123-52940c376ce8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_dd0c46fb-1c7b-4bbf-b4f9-b7ae822cb555" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_de78c1fd-00f5-46d0-b123-52940c376ce8" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_dd0c46fb-1c7b-4bbf-b4f9-b7ae822cb555" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_2e6f25e3-6d7f-4cf1-8b26-1ef82cbc5d66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_dd0c46fb-1c7b-4bbf-b4f9-b7ae822cb555" xlink:to="loc_us-gaap_OtherAssetsMember_2e6f25e3-6d7f-4cf1-8b26-1ef82cbc5d66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_96ff695f-58ab-44e0-a0f1-dedc9d9f6448" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_dd0c46fb-1c7b-4bbf-b4f9-b7ae822cb555" xlink:to="loc_us-gaap_OtherLiabilitiesMember_96ff695f-58ab-44e0-a0f1-dedc9d9f6448" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0141cd3c-cbc9-4907-8a3f-641590bdb7dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2503079f-cccf-4d3d-98f8-8a06ca83c20d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0141cd3c-cbc9-4907-8a3f-641590bdb7dd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0141cd3c-cbc9-4907-8a3f-641590bdb7dd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0141cd3c-cbc9-4907-8a3f-641590bdb7dd" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0141cd3c-cbc9-4907-8a3f-641590bdb7dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4e846dd8-2431-405e-9c12-98cf5d44e94a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0141cd3c-cbc9-4907-8a3f-641590bdb7dd" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4e846dd8-2431-405e-9c12-98cf5d44e94a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAcquiredInPlaceMember_1bc5697e-3de1-44db-aa84-cc61253aa424" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAcquiredInPlaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4e846dd8-2431-405e-9c12-98cf5d44e94a" xlink:to="loc_us-gaap_LeasesAcquiredInPlaceMember_1bc5697e-3de1-44db-aa84-cc61253aa424" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AboveMarketLeasesMember_36320c49-af9d-4fcb-89af-f61dcfbfe0bd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AboveMarketLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4e846dd8-2431-405e-9c12-98cf5d44e94a" xlink:to="loc_us-gaap_AboveMarketLeasesMember_36320c49-af9d-4fcb-89af-f61dcfbfe0bd" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/RealEstate2020PropertyAcquisitionsandDispositionsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#RealEstate2020PropertyAcquisitionsandDispositionsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/RealEstate2020PropertyAcquisitionsandDispositionsDetails" xlink:type="extended" id="i82c0e31d72314b679ff93e5add91695e_RealEstate2020PropertyAcquisitionsandDispositionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_f71d14c3-24aa-41a8-9850-18417c9f85cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_f71d14c3-24aa-41a8-9850-18417c9f85cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Purchasepriceofrealestateacquisition_a51128c8-fe27-4ae6-8e78-4411110b3726" xlink:href="frt-20211231.xsd#frt_Purchasepriceofrealestateacquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_frt_Purchasepriceofrealestateacquisition_a51128c8-fe27-4ae6-8e78-4411110b3726" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnitsOfPartnershipInterestAmount_d87f9967-3e05-412f-8d55-24033aba0184" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnitsOfPartnershipInterestAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_UnitsOfPartnershipInterestAmount_d87f9967-3e05-412f-8d55-24033aba0184" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_4c14380a-efff-44f9-bff1-135877a37b28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_4c14380a-efff-44f9-bff1-135877a37b28" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAcquired_225fdaf2-4c93-4683-81c1-7c4056122c50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_BelowMarketLeaseAcquired_225fdaf2-4c93-4683-81c1-7c4056122c50" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_99b383f9-b9aa-4af7-bdb7-537344b36254" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_99b383f9-b9aa-4af7-bdb7-537344b36254" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_50ae359f-903b-46f6-afa2-419016238a36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_50ae359f-903b-46f6-afa2-419016238a36" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetImpairmentCharges_79f04d59-f661-4deb-bcbf-3c498f9456cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_OtherAssetImpairmentCharges_79f04d59-f661-4deb-bcbf-3c498f9456cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentFairValueDisclosure_43ce2e41-4f64-4c19-8e48-43bea81d200f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentFairValueDisclosure_43ce2e41-4f64-4c19-8e48-43bea81d200f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfRealEstate_82665d18-0b6a-4d3e-9cc7-706e9b6b1935" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_ProceedsFromSaleOfRealEstate_82665d18-0b6a-4d3e-9cc7-706e9b6b1935" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_e50cd311-4feb-4ea7-a050-8c3149215bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_e50cd311-4feb-4ea7-a050-8c3149215bd4" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Numberofcondominiumunitssold_ee672168-33b2-45e2-923d-b1869508ea5e" xlink:href="frt-20211231.xsd#frt_Numberofcondominiumunitssold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_frt_Numberofcondominiumunitssold_ee672168-33b2-45e2-923d-b1869508ea5e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ff979369-2263-4cda-a017-b079e28a627f" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0fe60410-c578-4d25-8450-01aa01724247" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0fe60410-c578-4d25-8450-01aa01724247" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_0fe60410-c578-4d25-8450-01aa01724247_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0fe60410-c578-4d25-8450-01aa01724247" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_0fe60410-c578-4d25-8450-01aa01724247_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a05c11dd-41c0-4c45-95ed-3cf6dcee3efe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0fe60410-c578-4d25-8450-01aa01724247" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a05c11dd-41c0-4c45-95ed-3cf6dcee3efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CondominiumsMember_38ed4b62-5d35-47f3-b1fa-7819c040a15b" xlink:href="frt-20211231.xsd#frt_CondominiumsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a05c11dd-41c0-4c45-95ed-3cf6dcee3efe" xlink:to="loc_frt_CondominiumsMember_38ed4b62-5d35-47f3-b1fa-7819c040a15b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_a33302bf-46e5-4560-9642-f88b3b344503" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_a33302bf-46e5-4560-9642-f88b3b344503" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_a33302bf-46e5-4560-9642-f88b3b344503_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_a33302bf-46e5-4560-9642-f88b3b344503" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_a33302bf-46e5-4560-9642-f88b3b344503_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_d6e78ca0-45a7-41bc-887b-e232df8ec1eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_a33302bf-46e5-4560-9642-f88b3b344503" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_d6e78ca0-45a7-41bc-887b-e232df8ec1eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_f786bf39-5c79-48d5-a279-a30f2a8c8ad3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d6e78ca0-45a7-41bc-887b-e232df8ec1eb" xlink:to="loc_us-gaap_OtherAssetsMember_f786bf39-5c79-48d5-a279-a30f2a8c8ad3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_3d4ce0d1-33c1-4123-969f-1137f9d0d3ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d6e78ca0-45a7-41bc-887b-e232df8ec1eb" xlink:to="loc_us-gaap_OtherLiabilitiesMember_3d4ce0d1-33c1-4123-969f-1137f9d0d3ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_95cc4723-9015-4dfa-86da-bfde28e1eac2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_95cc4723-9015-4dfa-86da-bfde28e1eac2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_95cc4723-9015-4dfa-86da-bfde28e1eac2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_95cc4723-9015-4dfa-86da-bfde28e1eac2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_95cc4723-9015-4dfa-86da-bfde28e1eac2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8f414d9e-93d3-47b2-ab23-78bd5c514a02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_95cc4723-9015-4dfa-86da-bfde28e1eac2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8f414d9e-93d3-47b2-ab23-78bd5c514a02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AboveMarketLeasesMember_eb24649c-7029-4099-890a-8b1cdc03c315" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AboveMarketLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8f414d9e-93d3-47b2-ab23-78bd5c514a02" xlink:to="loc_us-gaap_AboveMarketLeasesMember_eb24649c-7029-4099-890a-8b1cdc03c315" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAcquiredInPlaceMember_7bc30d74-9b0a-4695-a345-7bc6d3cf3fdb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAcquiredInPlaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8f414d9e-93d3-47b2-ab23-78bd5c514a02" xlink:to="loc_us-gaap_LeasesAcquiredInPlaceMember_7bc30d74-9b0a-4695-a345-7bc6d3cf3fdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_cc9099a9-0c72-46d0-a265-015610b11992" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_cc9099a9-0c72-46d0-a265-015610b11992" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_cc9099a9-0c72-46d0-a265-015610b11992_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_cc9099a9-0c72-46d0-a265-015610b11992" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_cc9099a9-0c72-46d0-a265-015610b11992_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_cc9099a9-0c72-46d0-a265-015610b11992" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseHotelJVMember_804aa563-a6b1-4b51-afdc-b3af73cacb77" xlink:href="frt-20211231.xsd#frt_PikeRoseHotelJVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_PikeRoseHotelJVMember_804aa563-a6b1-4b51-afdc-b3af73cacb77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MountVernonMember_1813914c-b28a-446f-910e-43da4669a240" xlink:href="frt-20211231.xsd#frt_MountVernonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_MountVernonMember_1813914c-b28a-446f-910e-43da4669a240" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ChesterbrookMember_6952bb83-fd6a-4112-9e67-76fe194aca06" xlink:href="frt-20211231.xsd#frt_ChesterbrookMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_ChesterbrookMember_6952bb83-fd6a-4112-9e67-76fe194aca06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrossmontCenterMember_055d2a51-d52f-49f8-a33e-34a5b3026a60" xlink:href="frt-20211231.xsd#frt_GrossmontCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_GrossmontCenterMember_055d2a51-d52f-49f8-a33e-34a5b3026a60" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CamelbackColonnadeMember_64c965ea-d389-4df7-959e-b6d8338ea435" xlink:href="frt-20211231.xsd#frt_CamelbackColonnadeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_CamelbackColonnadeMember_64c965ea-d389-4df7-959e-b6d8338ea435" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HiltonVillageMember_0fe082d0-eeec-4c1e-a495-84e9ae4bcbce" xlink:href="frt-20211231.xsd#frt_HiltonVillageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_HiltonVillageMember_0fe082d0-eeec-4c1e-a495-84e9ae4bcbce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TwinbrookeShoppingCentreMember_b5a1dc8a-aef4-413d-a007-4ebaa0fad094" xlink:href="frt-20211231.xsd#frt_TwinbrookeShoppingCentreMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_TwinbrookeShoppingCentreMember_b5a1dc8a-aef4-413d-a007-4ebaa0fad094" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TwoProperties2021Member_163879be-fc77-4a1e-815c-2be13facf073" xlink:href="frt-20211231.xsd#frt_TwoProperties2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_TwoProperties2021Member_163879be-fc77-4a1e-815c-2be13facf073" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FairfaxJunctionMember_fd4c0aac-cc6b-477f-a08f-ac268e432b85" xlink:href="frt-20211231.xsd#frt_FairfaxJunctionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_FairfaxJunctionMember_fd4c0aac-cc6b-477f-a08f-ac268e432b85" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_e2fa610e-6213-4fbd-836c-f8abc690ae93" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_HobokenMember_e2fa610e-6213-4fbd-836c-f8abc690ae93" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SunsetPlaceMember_9cfc4069-78d5-410d-af95-fda83cc6badb" xlink:href="frt-20211231.xsd#frt_SunsetPlaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_SunsetPlaceMember_9cfc4069-78d5-410d-af95-fda83cc6badb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Hoboken2BuildingsMember_8b8648f9-53e9-4224-9ac1-5032f265b9d5" xlink:href="frt-20211231.xsd#frt_Hoboken2BuildingsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_Hoboken2BuildingsMember_8b8648f9-53e9-4224-9ac1-5032f265b9d5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ThreeProperties2020Member_b2b4ee6d-583b-4c01-ae51-79ad6a9facd2" xlink:href="frt-20211231.xsd#frt_ThreeProperties2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_ThreeProperties2020Member_b2b4ee6d-583b-4c01-ae51-79ad6a9facd2" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseMember_b1ca583d-66a6-45d5-b03d-53bb41ae9d57" xlink:href="frt-20211231.xsd#frt_PikeRoseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_efdadefd-e167-4e8d-867c-94f6566abda4" xlink:to="loc_frt_PikeRoseMember_b1ca583d-66a6-45d5-b03d-53bb41ae9d57" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusAxis_1e05c085-543a-45f4-92cb-cf019f7f6875" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_RecourseStatusAxis_1e05c085-543a-45f4-92cb-cf019f7f6875" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusDomain_1e05c085-543a-45f4-92cb-cf019f7f6875_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RecourseStatusAxis_1e05c085-543a-45f4-92cb-cf019f7f6875" xlink:to="loc_us-gaap_RecourseStatusDomain_1e05c085-543a-45f4-92cb-cf019f7f6875_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusDomain_e34ebb0a-278a-4c7d-898b-04ded195e75f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RecourseStatusAxis_1e05c085-543a-45f4-92cb-cf019f7f6875" xlink:to="loc_us-gaap_RecourseStatusDomain_e34ebb0a-278a-4c7d-898b-04ded195e75f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrecourseMember_6e57eb19-757a-4edd-a403-387a61e310b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonrecourseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RecourseStatusDomain_e34ebb0a-278a-4c7d-898b-04ded195e75f" xlink:to="loc_us-gaap_NonrecourseMember_6e57eb19-757a-4edd-a403-387a61e310b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_4b3a7174-0305-46a3-8372-952a5b69e22c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_4b3a7174-0305-46a3-8372-952a5b69e22c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_4b3a7174-0305-46a3-8372-952a5b69e22c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_4b3a7174-0305-46a3-8372-952a5b69e22c" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_4b3a7174-0305-46a3-8372-952a5b69e22c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_641a684b-a20a-4fe2-ae6b-c3eb32281832" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_4b3a7174-0305-46a3-8372-952a5b69e22c" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_641a684b-a20a-4fe2-ae6b-c3eb32281832" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseHotelJVMember_2af7d336-0d4c-40ef-a397-0a474e67d616" xlink:href="frt-20211231.xsd#frt_PikeRoseHotelJVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_641a684b-a20a-4fe2-ae6b-c3eb32281832" xlink:to="loc_frt_PikeRoseHotelJVMember_2af7d336-0d4c-40ef-a397-0a474e67d616" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_7236b114-b1b3-48cf-abc5-f3146beb1e3d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_7236b114-b1b3-48cf-abc5-f3146beb1e3d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_7236b114-b1b3-48cf-abc5-f3146beb1e3d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_7236b114-b1b3-48cf-abc5-f3146beb1e3d" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_7236b114-b1b3-48cf-abc5-f3146beb1e3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_580eb892-a626-4244-8ccf-cb4d332ceb5f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_7236b114-b1b3-48cf-abc5-f3146beb1e3d" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_580eb892-a626-4244-8ccf-cb4d332ceb5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseHotelJVMember_32c6e88e-af52-442a-a060-eaccc05abef3" xlink:href="frt-20211231.xsd#frt_PikeRoseHotelJVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_580eb892-a626-4244-8ccf-cb4d332ceb5f" xlink:to="loc_frt_PikeRoseHotelJVMember_32c6e88e-af52-442a-a060-eaccc05abef3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_26a42069-8ad7-4943-9b0c-204b4d6dfe5b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_85b34fd7-afd8-4d5d-be2b-c329ee3033cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5a3056b8-b9e8-4eb3-bcda-59b455bf88d8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_85b34fd7-afd8-4d5d-be2b-c329ee3033cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesMember_3b5cd372-424f-4f0c-9503-595504ef7c8f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgagesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_85b34fd7-afd8-4d5d-be2b-c329ee3033cd" xlink:to="loc_us-gaap_MortgagesMember_3b5cd372-424f-4f0c-9503-595504ef7c8f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/AcquiredInPlaceLeasesAcquredLeaseAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#AcquiredInPlaceLeasesAcquredLeaseAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/AcquiredInPlaceLeasesAcquredLeaseAssetsandLiabilitiesDetails" xlink:type="extended" id="ieca2af57d7fc45d8b67d58254991b005_AcquiredInPlaceLeasesAcquredLeaseAssetsandLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_44860732-46ea-4f31-a568-021a7f944d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_44860732-46ea-4f31-a568-021a7f944d3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_30c996b1-159b-4d89-a246-ca888ae456a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_30c996b1-159b-4d89-a246-ca888ae456a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FiniteLivedIntangibleLiabilitiesGross_76ee3f22-f2ec-4772-8594-7757f21fe729" xlink:href="frt-20211231.xsd#frt_FiniteLivedIntangibleLiabilitiesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_FiniteLivedIntangibleLiabilitiesGross_76ee3f22-f2ec-4772-8594-7757f21fe729" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization_48331b3e-ad75-419f-80b7-792da9fe9205" xlink:href="frt-20211231.xsd#frt_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization_48331b3e-ad75-419f-80b7-792da9fe9205" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_55bdce7a-4c1c-4da2-96c8-b31b5c815a59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_55bdce7a-4c1c-4da2-96c8-b31b5c815a59" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfBelowMarketLease_d5136e7f-c596-419b-9dff-33ef0d74ebf0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfBelowMarketLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_AmortizationOfBelowMarketLease_d5136e7f-c596-419b-9dff-33ef0d74ebf0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfAboveAndBelowMarketLeases_8b00c3ee-3ede-4694-8418-405e7c7669ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfAboveAndBelowMarketLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_AmortizationOfAboveAndBelowMarketLeases_8b00c3ee-3ede-4694-8418-405e7c7669ac" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AmortizationofBelowMarketLeaseLessee_187045a2-22bc-43a0-aeef-649e7c49ace7" xlink:href="frt-20211231.xsd#frt_AmortizationofBelowMarketLeaseLessee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_AmortizationofBelowMarketLeaseLessee_187045a2-22bc-43a0-aeef-649e7c49ace7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AmortizationOfIntangibleLiability_9fb9bcc3-53fb-40b9-b45a-5f1d728e0215" xlink:href="frt-20211231.xsd#frt_AmortizationOfIntangibleLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_AmortizationOfIntangibleLiability_9fb9bcc3-53fb-40b9-b45a-5f1d728e0215" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AmortizationOfAboveAndBelowMarketLeasesLessee_27266078-c44b-4974-8fc5-7aaa15562403" xlink:href="frt-20211231.xsd#frt_AmortizationOfAboveAndBelowMarketLeasesLessee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_AmortizationOfAboveAndBelowMarketLeasesLessee_27266078-c44b-4974-8fc5-7aaa15562403" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_57772178-5b83-4963-bd23-0add661d5e48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_57772178-5b83-4963-bd23-0add661d5e48" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AcquiredFiniteLivedIntangibleLiabilitiesWeightedAverageUsefulLife_81f88de4-3524-484f-baeb-81839fbcdff6" xlink:href="frt-20211231.xsd#frt_AcquiredFiniteLivedIntangibleLiabilitiesWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_frt_AcquiredFiniteLivedIntangibleLiabilitiesWeightedAverageUsefulLife_81f88de4-3524-484f-baeb-81839fbcdff6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_d5702317-0563-401e-9559-970157a6a807" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_d5702317-0563-401e-9559-970157a6a807" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_67340ea0-3aa4-450e-b298-70152dcce12c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_67340ea0-3aa4-450e-b298-70152dcce12c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_79c56955-6876-4be8-9af1-9778170653d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_79c56955-6876-4be8-9af1-9778170653d0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_60a598e2-2a45-4025-8319-0efc04df9137" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_60a598e2-2a45-4025-8319-0efc04df9137" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ac0d3c2c-a2fb-43a2-ab59-b6f894e5ad35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ac0d3c2c-a2fb-43a2-ab59-b6f894e5ad35" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_931a37b9-14d8-45a6-a7bb-4961e5fa8a7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_65de9c85-f62d-4bea-91ab-114ff644af86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_931a37b9-14d8-45a6-a7bb-4961e5fa8a7b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths_656eea37-2508-4256-8cda-4b8e8b626025" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths_656eea37-2508-4256-8cda-4b8e8b626025" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo_68fda5d4-f47b-44fe-a618-e8642345a036" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo_68fda5d4-f47b-44fe-a618-e8642345a036" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearThree_9cdd93db-23d9-4da6-9d5d-73fdc581112e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearThree_9cdd93db-23d9-4da6-9d5d-73fdc581112e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFour_a435309d-3f1e-40d5-86b9-a79c28430284" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFour_a435309d-3f1e-40d5-86b9-a79c28430284" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFive_722dc03b-9aff-464d-897d-fd7d64a0476b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFive_722dc03b-9aff-464d-897d-fd7d64a0476b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeAfterYearFive_211a2f89-cd86-4c7b-bd68-903a86f3685a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeAfterYearFive_211a2f89-cd86-4c7b-bd68-903a86f3685a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e45832c5-b88b-4e71-8cdc-93bbbb7946a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e45832c5-b88b-4e71-8cdc-93bbbb7946a7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseNet_bddfa796-2746-4f8c-a7b1-beecf349982b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BelowMarketLeaseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BelowMarketLeaseAmortizationIncomeMaturityScheduleAbstract_6ce577cf-0951-4e02-b955-62cd962ecfa3" xlink:to="loc_us-gaap_BelowMarketLeaseNet_bddfa796-2746-4f8c-a7b1-beecf349982b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_fe831c31-4868-4ab3-ba7c-bc97f834c76c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_6f4611a1-c2eb-4c06-9c0d-9483f3ed6f8e" xlink:to="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_fe831c31-4868-4ab3-ba7c-bc97f834c76c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassAxis_fe46e93d-92b6-44bf-acd9-cf426de69516" xlink:href="frt-20211231.xsd#frt_FiniteLivedIntangibleLiabilitiesByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_fe831c31-4868-4ab3-ba7c-bc97f834c76c" xlink:to="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassAxis_fe46e93d-92b6-44bf-acd9-cf426de69516" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_fe46e93d-92b6-44bf-acd9-cf426de69516_default" xlink:href="frt-20211231.xsd#frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassAxis_fe46e93d-92b6-44bf-acd9-cf426de69516" xlink:to="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_fe46e93d-92b6-44bf-acd9-cf426de69516_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_053dba02-2079-4f94-9a32-a92cb5caa276" xlink:href="frt-20211231.xsd#frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassAxis_fe46e93d-92b6-44bf-acd9-cf426de69516" xlink:to="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_053dba02-2079-4f94-9a32-a92cb5caa276" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BelowMarketLeasesLessorMember_36188a6f-c708-4ef1-b325-60cb44df2b24" xlink:href="frt-20211231.xsd#frt_BelowMarketLeasesLessorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_053dba02-2079-4f94-9a32-a92cb5caa276" xlink:to="loc_frt_BelowMarketLeasesLessorMember_36188a6f-c708-4ef1-b325-60cb44df2b24" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AboveMarketLeasesLesseeMember_fd41dcad-9415-4d27-acc3-de5f086b7785" xlink:href="frt-20211231.xsd#frt_AboveMarketLeasesLesseeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_FiniteLivedIntangibleLiabilitiesByMajorClassDomain_053dba02-2079-4f94-9a32-a92cb5caa276" xlink:to="loc_frt_AboveMarketLeasesLesseeMember_fd41dcad-9415-4d27-acc3-de5f086b7785" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_51d1774a-5087-4194-a8ab-d908fcb49343" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_fe831c31-4868-4ab3-ba7c-bc97f834c76c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_51d1774a-5087-4194-a8ab-d908fcb49343" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_51d1774a-5087-4194-a8ab-d908fcb49343_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_51d1774a-5087-4194-a8ab-d908fcb49343" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_51d1774a-5087-4194-a8ab-d908fcb49343_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_51d1774a-5087-4194-a8ab-d908fcb49343" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AboveMarketLeasesMember_e3cb94cc-883d-41d5-abf1-8a404a85a92f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AboveMarketLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:to="loc_us-gaap_AboveMarketLeasesMember_e3cb94cc-883d-41d5-abf1-8a404a85a92f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AboveMarketLeasesLessorMember_b0f9ee16-2667-44f4-b769-0c8c61566c94" xlink:href="frt-20211231.xsd#frt_AboveMarketLeasesLessorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:to="loc_frt_AboveMarketLeasesLessorMember_b0f9ee16-2667-44f4-b769-0c8c61566c94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BelowMarketLeasesLesseeMember_47915a8a-b68e-4681-ac73-dfdc8249deb2" xlink:href="frt-20211231.xsd#frt_BelowMarketLeasesLesseeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:to="loc_frt_BelowMarketLeasesLesseeMember_47915a8a-b68e-4681-ac73-dfdc8249deb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BelowMarketLeaseMember_fe0f4667-05d6-44a6-8f57-2971ca5a9a2c" xlink:href="frt-20211231.xsd#frt_BelowMarketLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0ff51b9-c8f1-4a58-ad5a-89a580c3e2c0" xlink:to="loc_frt_BelowMarketLeaseMember_fe0f4667-05d6-44a6-8f57-2971ca5a9a2c" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/DebtSummaryOfDebtOutstandingDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#DebtSummaryOfDebtOutstandingDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DebtSummaryOfDebtOutstandingDetails" xlink:type="extended" id="i6afc6538a5b541afa7335e49c24baa64_DebtSummaryOfDebtOutstandingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_38e391b0-1b11-4e0b-84bb-50b3c0de618a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_38e391b0-1b11-4e0b-84bb-50b3c0de618a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_7153d0a6-4ca8-48c7-bf85-4f85701175af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_7153d0a6-4ca8-48c7-bf85-4f85701175af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4bbc1509-afb9-4342-8a7d-726534b499ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4bbc1509-afb9-4342-8a7d-726534b499ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_8dc38769-4246-4160-9ca3-4d0f561d2175" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_SecuredDebt_8dc38769-4246-4160-9ca3-4d0f561d2175" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_ce543358-e18b-4fce-968e-7bff61490293" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_LineOfCredit_ce543358-e18b-4fce-968e-7bff61490293" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNotesPayable_4bed5437-12dc-458a-bccb-55cdbec7f1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_OtherNotesPayable_4bed5437-12dc-458a-bccb-55cdbec7f1b7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayable_c20dcc42-6c0f-4efa-93f7-c355b3a3ad5f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_NotesPayable_c20dcc42-6c0f-4efa-93f7-c355b3a3ad5f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_99229db9-4f4e-4b78-88f9-9e84e76ae9e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_99229db9-4f4e-4b78-88f9-9e84e76ae9e2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_5b35a5b4-64ba-4601-8fbd-4538d21204b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_5b35a5b4-64ba-4601-8fbd-4538d21204b5" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotes_a674b22c-d960-4612-876e-b94ec16ff685" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_SeniorNotes_a674b22c-d960-4612-876e-b94ec16ff685" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_f14982ab-1660-4898-a92c-54c59e1da6d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_f14982ab-1660-4898-a92c-54c59e1da6d5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfInterestRateDerivativesHeld_e027b23c-3aff-4286-90b6-a7d642ef3c7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfInterestRateDerivativesHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_NumberOfInterestRateDerivativesHeld_e027b23c-3aff-4286-90b6-a7d642ef3c7d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_5f0236dc-d60a-4c06-9d7c-ca0a9b045d25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_5f0236dc-d60a-4c06-9d7c-ca0a9b045d25" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_5739ccc4-1cf1-4162-8f08-6c2beaebb621" xlink:to="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_a8862238-dd55-44dd-90af-716715f71374" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:to="loc_srt_RangeAxis_a8862238-dd55-44dd-90af-716715f71374" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a8862238-dd55-44dd-90af-716715f71374_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_a8862238-dd55-44dd-90af-716715f71374" xlink:to="loc_srt_RangeMember_a8862238-dd55-44dd-90af-716715f71374_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f53df53a-6451-48f6-8dbd-793572697d3f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_a8862238-dd55-44dd-90af-716715f71374" xlink:to="loc_srt_RangeMember_f53df53a-6451-48f6-8dbd-793572697d3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_12639d2c-6ebc-475f-9152-bee7324c67a6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f53df53a-6451-48f6-8dbd-793572697d3f" xlink:to="loc_srt_MinimumMember_12639d2c-6ebc-475f-9152-bee7324c67a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_1c5cd7fe-174f-4811-8457-68172168d048" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f53df53a-6451-48f6-8dbd-793572697d3f" xlink:to="loc_srt_MaximumMember_1c5cd7fe-174f-4811-8457-68172168d048" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4369eccd-ed8d-41fd-99c8-8af190039f44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:to="loc_us-gaap_DebtInstrumentAxis_4369eccd-ed8d-41fd-99c8-8af190039f44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4369eccd-ed8d-41fd-99c8-8af190039f44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4369eccd-ed8d-41fd-99c8-8af190039f44" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4369eccd-ed8d-41fd-99c8-8af190039f44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4369eccd-ed8d-41fd-99c8-8af190039f44" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SylmarTowneCenterMember_9615e790-4a60-440e-a0c6-4483ee001d11" xlink:href="frt-20211231.xsd#frt_SylmarTowneCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_SylmarTowneCenterMember_9615e790-4a60-440e-a0c6-4483ee001d11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaDelSolMember_f4614a9e-caab-4e09-bfed-4912605ee5d1" xlink:href="frt-20211231.xsd#frt_PlazaDelSolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_PlazaDelSolMember_f4614a9e-caab-4e09-bfed-4912605ee5d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_THEAVENUEatWhiteMarshDue2021Member_44cd89c3-1c64-42ca-9d12-eed03bde3f2f" xlink:href="frt-20211231.xsd#frt_THEAVENUEatWhiteMarshDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_THEAVENUEatWhiteMarshDue2021Member_44cd89c3-1c64-42ca-9d12-eed03bde3f2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MontroseCrossingMember_c03c0392-7a20-4783-abfb-43c332c581ad" xlink:href="frt-20211231.xsd#frt_MontroseCrossingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_MontroseCrossingMember_c03c0392-7a20-4783-abfb-43c332c581ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AzaleaMember_76c28dd0-8117-4420-9244-935901690dbc" xlink:href="frt-20211231.xsd#frt_AzaleaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_AzaleaMember_76c28dd0-8117-4420-9244-935901690dbc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BellGardensMember_97cff831-84db-4a2e-b859-7bed3fa519f1" xlink:href="frt-20211231.xsd#frt_BellGardensMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_BellGardensMember_97cff831-84db-4a2e-b859-7bed3fa519f1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaElSegundoMember_2794d605-9307-48ea-975e-c5508996286c" xlink:href="frt-20211231.xsd#frt_PlazaElSegundoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_PlazaElSegundoMember_2794d605-9307-48ea-975e-c5508996286c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Brook35Member_e5f48fe9-84d1-4dfd-97c9-2b709de7df5d" xlink:href="frt-20211231.xsd#frt_Brook35Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Brook35Member_e5f48fe9-84d1-4dfd-97c9-2b709de7df5d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Hoboken24BuildingsMember_3414cb8c-7dca-49c8-b9a2-f6648d1c1967" xlink:href="frt-20211231.xsd#frt_Hoboken24BuildingsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Hoboken24BuildingsMember_3414cb8c-7dca-49c8-b9a2-f6648d1c1967" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GroveatShrewsburyEastMember_7082e2ed-a068-406b-87d1-6f70d2c6d173" xlink:href="frt-20211231.xsd#frt_GroveatShrewsburyEastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_GroveatShrewsburyEastMember_7082e2ed-a068-406b-87d1-6f70d2c6d173" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Hoboken14BuildingsMember_1235eaf4-02f9-4a23-83d7-dddd7aa230b5" xlink:href="frt-20211231.xsd#frt_Hoboken14BuildingsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Hoboken14BuildingsMember_1235eaf4-02f9-4a23-83d7-dddd7aa230b5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ChelseaMember_aa8f9482-fb12-42a2-9657-15b157e86f88" xlink:href="frt-20211231.xsd#frt_ChelseaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_ChelseaMember_aa8f9482-fb12-42a2-9657-15b157e86f88" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Hoboken21014thStreetMember_dbf38315-a97a-41fd-acb9-7e0fde042e60" xlink:href="frt-20211231.xsd#frt_Hoboken21014thStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Hoboken21014thStreetMember_dbf38315-a97a-41fd-acb9-7e0fde042e60" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TermloanMember_520259cf-8625-4c3c-b069-d648251e941b" xlink:href="frt-20211231.xsd#frt_TermloanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_TermloanMember_520259cf-8625-4c3c-b069-d648251e941b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_VariousNotesPayableMember_b28469b7-564d-4208-893c-a7a4f841341b" xlink:href="frt-20211231.xsd#frt_VariousNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_VariousNotesPayableMember_b28469b7-564d-4208-893c-a7a4f841341b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior2Point75PercentNotesMember_713c76e8-f14c-418b-b16d-06fd2ea40a0f" xlink:href="frt-20211231.xsd#frt_Senior2Point75PercentNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Senior2Point75PercentNotesMember_713c76e8-f14c-418b-b16d-06fd2ea40a0f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior395percentnotesMember_2f913356-d359-4e15-9291-645f3aee3a69" xlink:href="frt-20211231.xsd#frt_Senior395percentnotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Senior395percentnotesMember_2f913356-d359-4e15-9291-645f3aee3a69" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Debentures748PercentMember_9627fa94-6c98-4f43-865e-a5f3c3f2d2d8" xlink:href="frt-20211231.xsd#frt_Debentures748PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_Debentures748PercentMember_9627fa94-6c98-4f43-865e-a5f3c3f2d2d8" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A3.25SeniornotesMember_fc3249f1-5d11-4803-a572-8391c25d3229" xlink:href="frt-20211231.xsd#frt_A3.25SeniornotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A3.25SeniornotesMember_fc3249f1-5d11-4803-a572-8391c25d3229" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MediumTermNotes682PercentMember_67bbbf41-a9c6-4874-8bd3-0866e643e1ed" xlink:href="frt-20211231.xsd#frt_MediumTermNotes682PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_MediumTermNotes682PercentMember_67bbbf41-a9c6-4874-8bd3-0866e643e1ed" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A3.2SeniorNoteMember_bae9285c-7da8-4964-bc08-6368ed29942b" xlink:href="frt-20211231.xsd#frt_A3.2SeniorNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A3.2SeniorNoteMember_bae9285c-7da8-4964-bc08-6368ed29942b" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A4.50SeniornotesMember_4f769f94-76ad-4658-9c32-8be02dac06e6" xlink:href="frt-20211231.xsd#frt_A4.50SeniornotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A4.50SeniornotesMember_4f769f94-76ad-4658-9c32-8be02dac06e6" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A3.625SeniornotesMember_2dd0529e-d91c-455d-bd57-89462286da4d" xlink:href="frt-20211231.xsd#frt_A3.625SeniornotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A3.625SeniornotesMember_2dd0529e-d91c-455d-bd57-89462286da4d" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A125SeniorNoteMember_9dbd8a0c-0032-4468-823c-a43b97f1043f" xlink:href="frt-20211231.xsd#frt_A125SeniorNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A125SeniorNoteMember_9dbd8a0c-0032-4468-823c-a43b97f1043f" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A35SeniorNoteMember_e529495a-b658-4b3b-86d0-26df200ac79f" xlink:href="frt-20211231.xsd#frt_A35SeniorNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_A35SeniorNoteMember_e529495a-b658-4b3b-86d0-26df200ac79f" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_e7eb7159-fd34-4467-a05f-b7a3c970e4a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_e7eb7159-fd34-4467-a05f-b7a3c970e4a6" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_edb8ed36-f70e-455e-9333-7b6d428506e9" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9a71c8b-eddd-4386-baa2-d4e5a663fe0a" xlink:to="loc_frt_HobokenMember_edb8ed36-f70e-455e-9333-7b6d428506e9" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_58263a56-0fb9-4891-b7f9-dd44c5d06a68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_58263a56-0fb9-4891-b7f9-dd44c5d06a68" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_58263a56-0fb9-4891-b7f9-dd44c5d06a68_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_58263a56-0fb9-4891-b7f9-dd44c5d06a68" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_58263a56-0fb9-4891-b7f9-dd44c5d06a68_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_58263a56-0fb9-4891-b7f9-dd44c5d06a68" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_04bdb409-cf22-421e-bec1-2b3006d4f45d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:to="loc_us-gaap_SecuredDebtMember_04bdb409-cf22-421e-bec1-2b3006d4f45d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_0f598721-3e69-49ed-afcc-c819c0b18147" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_0f598721-3e69-49ed-afcc-c819c0b18147" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_64ee2a89-b773-484b-94b4-b8ea4a59dd7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:to="loc_us-gaap_SeniorNotesMember_64ee2a89-b773-484b-94b4-b8ea4a59dd7e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TermloanMember_46aa1d1a-2e43-4eeb-95eb-e3bcb7d07b87" xlink:href="frt-20211231.xsd#frt_TermloanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bf5e91d6-370b-40b4-8dc1-b897621eccf6" xlink:to="loc_frt_TermloanMember_46aa1d1a-2e43-4eeb-95eb-e3bcb7d07b87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_096baea3-0340-4c00-af33-38cd49eeb172" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7be857cc-57c4-4f93-ba10-91eea87bae30" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_096baea3-0340-4c00-af33-38cd49eeb172" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_096baea3-0340-4c00-af33-38cd49eeb172_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_096baea3-0340-4c00-af33-38cd49eeb172" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_096baea3-0340-4c00-af33-38cd49eeb172_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_096baea3-0340-4c00-af33-38cd49eeb172" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SylmarTowneCenterMember_0305f829-bcf9-45c9-a580-90177792633a" xlink:href="frt-20211231.xsd#frt_SylmarTowneCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:to="loc_frt_SylmarTowneCenterMember_0305f829-bcf9-45c9-a580-90177792633a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaDelSolMember_a5e14490-89fa-4219-8bf4-989c3060a489" xlink:href="frt-20211231.xsd#frt_PlazaDelSolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:to="loc_frt_PlazaDelSolMember_a5e14490-89fa-4219-8bf4-989c3060a489" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MontroseCrossingMember_48ff3aae-846f-44b1-9c83-bff7c68c8db8" xlink:href="frt-20211231.xsd#frt_MontroseCrossingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:to="loc_frt_MontroseCrossingMember_48ff3aae-846f-44b1-9c83-bff7c68c8db8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AvenueAtWhiteMarshMember_bc913aaf-80c3-4987-9064-85234cdad41e" xlink:href="frt-20211231.xsd#frt_AvenueAtWhiteMarshMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1bf35778-4305-4ed1-91da-e7cd1447b485" xlink:to="loc_frt_AvenueAtWhiteMarshMember_bc913aaf-80c3-4987-9064-85234cdad41e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DebtNarrativeDetails" xlink:type="extended" id="id804389bd180432ba8e6fa1487bec016_DebtNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_2c840f2d-c601-4b9f-abfb-27d4f208f477" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_RepaymentsOfDebt_2c840f2d-c601-4b9f-abfb-27d4f208f477" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNotesPayable_024e4bed-0597-4045-845d-03205118192b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_OtherNotesPayable_024e4bed-0597-4045-845d-03205118192b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_fccbfea7-8f43-4e84-84cf-da2d1affc7a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_fccbfea7-8f43-4e84-84cf-da2d1affc7a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt_8cb8d8bc-1b7d-459b-b4a9-b92131f7fbaa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_RepaymentsOfSecuredDebt_8cb8d8bc-1b7d-459b-b4a9-b92131f7fbaa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_0607e064-2a8d-4886-9451-8330b8aaa112" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_LineOfCredit_0607e064-2a8d-4886-9451-8330b8aaa112" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_13e7a7c4-8970-4cc1-af23-a00dceb5a80e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_13e7a7c4-8970-4cc1-af23-a00dceb5a80e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod_61f73309-8182-448d-aa92-ffb1bcaa4393" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod_61f73309-8182-448d-aa92-ffb1bcaa4393" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAverageOutstandingAmount_a9bd36b4-4d85-4fd4-9269-e73c6ace5abe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_LineOfCreditFacilityAverageOutstandingAmount_a9bd36b4-4d85-4fd4-9269-e73c6ace5abe" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees_c9376b14-f4f5-4455-8e93-f5bd7df484d1" xlink:href="frt-20211231.xsd#frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees_c9376b14-f4f5-4455-8e93-f5bd7df484d1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Lineofcreditfacilityannualfacilityfee_2f5c7bc7-942e-45b5-86f4-3ffa85833280" xlink:href="frt-20211231.xsd#frt_Lineofcreditfacilityannualfacilityfee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_frt_Lineofcreditfacilityannualfacilityfee_2f5c7bc7-942e-45b5-86f4-3ffa85833280" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bb89c56f-faf8-431c-af52-4580e32340de" xlink:to="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_af21ebf0-309e-449d-8b51-2c3d678cb8ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_us-gaap_DebtInstrumentAxis_af21ebf0-309e-449d-8b51-2c3d678cb8ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_af21ebf0-309e-449d-8b51-2c3d678cb8ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_af21ebf0-309e-449d-8b51-2c3d678cb8ab" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_af21ebf0-309e-449d-8b51-2c3d678cb8ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c5fae55f-c7ed-4140-aaec-223ef04174e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_af21ebf0-309e-449d-8b51-2c3d678cb8ab" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c5fae55f-c7ed-4140-aaec-223ef04174e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TermloanMember_4fec857b-ac07-4ce7-ab0c-dcea373b9711" xlink:href="frt-20211231.xsd#frt_TermloanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c5fae55f-c7ed-4140-aaec-223ef04174e9" xlink:to="loc_frt_TermloanMember_4fec857b-ac07-4ce7-ab0c-dcea373b9711" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeAxis_b17cd494-70bc-4330-8edf-493cb26cf629" xlink:href="frt-20211231.xsd#frt_OptionByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_frt_OptionByTypeAxis_b17cd494-70bc-4330-8edf-493cb26cf629" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeDomain_b17cd494-70bc-4330-8edf-493cb26cf629_default" xlink:href="frt-20211231.xsd#frt_OptionByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_OptionByTypeAxis_b17cd494-70bc-4330-8edf-493cb26cf629" xlink:to="loc_frt_OptionByTypeDomain_b17cd494-70bc-4330-8edf-493cb26cf629_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeDomain_aafb67ed-f1d1-4cc2-810e-048f2e1e68da" xlink:href="frt-20211231.xsd#frt_OptionByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_OptionByTypeAxis_b17cd494-70bc-4330-8edf-493cb26cf629" xlink:to="loc_frt_OptionByTypeDomain_aafb67ed-f1d1-4cc2-810e-048f2e1e68da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_29e4a623-e14c-485f-a01c-8624ce45402d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_29e4a623-e14c-485f-a01c-8624ce45402d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_29e4a623-e14c-485f-a01c-8624ce45402d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_29e4a623-e14c-485f-a01c-8624ce45402d" xlink:to="loc_us-gaap_RelatedPartyDomain_29e4a623-e14c-485f-a01c-8624ce45402d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_841f5658-7f9d-480c-aa88-f23781b209f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_29e4a623-e14c-485f-a01c-8624ce45402d" xlink:to="loc_us-gaap_RelatedPartyDomain_841f5658-7f9d-480c-aa88-f23781b209f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_61ece2b9-d422-4ef0-b947-5fd6a3b73f88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_61ece2b9-d422-4ef0-b947-5fd6a3b73f88" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_61ece2b9-d422-4ef0-b947-5fd6a3b73f88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_61ece2b9-d422-4ef0-b947-5fd6a3b73f88" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_61ece2b9-d422-4ef0-b947-5fd6a3b73f88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5fc2533d-7f7f-4e40-835b-438d00b5171b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_61ece2b9-d422-4ef0-b947-5fd6a3b73f88" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5fc2533d-7f7f-4e40-835b-438d00b5171b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TermloanMember_1fe46b99-0162-414a-96d1-1f68bb3488af" xlink:href="frt-20211231.xsd#frt_TermloanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5fc2533d-7f7f-4e40-835b-438d00b5171b" xlink:to="loc_frt_TermloanMember_1fe46b99-0162-414a-96d1-1f68bb3488af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_1aed494e-2506-453c-89e5-e1881929abc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5fc2533d-7f7f-4e40-835b-438d00b5171b" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_1aed494e-2506-453c-89e5-e1881929abc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_f373da97-4606-4cd5-beb2-f9998482aa25" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_f373da97-4606-4cd5-beb2-f9998482aa25" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_f373da97-4606-4cd5-beb2-f9998482aa25_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_f373da97-4606-4cd5-beb2-f9998482aa25" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_f373da97-4606-4cd5-beb2-f9998482aa25_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_f373da97-4606-4cd5-beb2-f9998482aa25" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SylmarTowneCenterMember_1e2c08f8-827d-4431-88ae-718e383ac795" xlink:href="frt-20211231.xsd#frt_SylmarTowneCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:to="loc_frt_SylmarTowneCenterMember_1e2c08f8-827d-4431-88ae-718e383ac795" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaDelSolMember_76f911a7-4ffa-4ee9-a89c-df94454f0c35" xlink:href="frt-20211231.xsd#frt_PlazaDelSolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:to="loc_frt_PlazaDelSolMember_76f911a7-4ffa-4ee9-a89c-df94454f0c35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MontroseCrossingMember_f8c91fc6-0631-4e03-ae49-13c2f26087be" xlink:href="frt-20211231.xsd#frt_MontroseCrossingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:to="loc_frt_MontroseCrossingMember_f8c91fc6-0631-4e03-ae49-13c2f26087be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AvenueAtWhiteMarshMember_9bf8ec7b-8cd7-40df-a6de-39f51d1ab523" xlink:href="frt-20211231.xsd#frt_AvenueAtWhiteMarshMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_241e687e-6ed7-49ff-85a4-bc322cf80a66" xlink:to="loc_frt_AvenueAtWhiteMarshMember_9bf8ec7b-8cd7-40df-a6de-39f51d1ab523" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusAxis_51101f07-a665-49b5-a77e-324b8f118c55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_39996b1d-5a8e-47d8-a6e7-36835e14b89c" xlink:to="loc_us-gaap_RecourseStatusAxis_51101f07-a665-49b5-a77e-324b8f118c55" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusDomain_51101f07-a665-49b5-a77e-324b8f118c55_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RecourseStatusAxis_51101f07-a665-49b5-a77e-324b8f118c55" xlink:to="loc_us-gaap_RecourseStatusDomain_51101f07-a665-49b5-a77e-324b8f118c55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecourseStatusDomain_ee52c7ee-3fe9-43da-bfe1-5022db401faa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecourseStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RecourseStatusAxis_51101f07-a665-49b5-a77e-324b8f118c55" xlink:to="loc_us-gaap_RecourseStatusDomain_ee52c7ee-3fe9-43da-bfe1-5022db401faa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrecourseMember_0d198295-f335-4775-ba9e-9d51428f73f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonrecourseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RecourseStatusDomain_ee52c7ee-3fe9-43da-bfe1-5022db401faa" xlink:to="loc_us-gaap_NonrecourseMember_0d198295-f335-4775-ba9e-9d51428f73f9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/DebtPrincipalPaymentsOnMortgagePayableNotesPayableSeniorNotesandDebenturesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#DebtPrincipalPaymentsOnMortgagePayableNotesPayableSeniorNotesandDebenturesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DebtPrincipalPaymentsOnMortgagePayableNotesPayableSeniorNotesandDebenturesDetails" xlink:type="extended" id="i79a743395e2340e7afd379eb2eee8a34_DebtPrincipalPaymentsOnMortgagePayableNotesPayableSeniorNotesandDebenturesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_31914333-7fac-4cc0-b34e-7be108ab8074" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_31914333-7fac-4cc0-b34e-7be108ab8074" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_d6cb40c0-7920-40c7-ba41-0ae7fc3fcc40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_d6cb40c0-7920-40c7-ba41-0ae7fc3fcc40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_0a25afee-a136-4bab-877b-f634cbeed17f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_0a25afee-a136-4bab-877b-f634cbeed17f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_680b9996-8ca0-45b8-b682-f60498e3d011" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_680b9996-8ca0-45b8-b682-f60498e3d011" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_7d3f92a3-aa9d-4a9f-b203-f41fa74ebf83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_7d3f92a3-aa9d-4a9f-b203-f41fa74ebf83" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_2616d895-55ce-41b5-9f1e-76844dba2b2f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_2616d895-55ce-41b5-9f1e-76844dba2b2f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_efd2c867-3eee-493b-8a6d-72ba3a0ee3db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_efd2c867-3eee-493b-8a6d-72ba3a0ee3db" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_06bb1ef8-3b0f-4e5a-9539-45102f9d5467" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LongTermDebt_06bb1ef8-3b0f-4e5a-9539-45102f9d5467" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_c2ab4cf0-8b26-42b2-a96a-9d660aa35a28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_c2ab4cf0-8b26-42b2-a96a-9d660aa35a28" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_7f196f7c-7c0b-4b3b-a96f-0b4db4850960" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_LineOfCredit_7f196f7c-7c0b-4b3b-a96f-0b4db4850960" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_d4688b45-2125-46ae-9863-11aa094186f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_fd398360-5d91-4749-8c17-5f77fec7d45a" xlink:to="loc_us-gaap_DebtInstrumentTable_d4688b45-2125-46ae-9863-11aa094186f0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_4e3dba35-58b9-487c-9fea-7bb31bae3c8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d4688b45-2125-46ae-9863-11aa094186f0" xlink:to="loc_us-gaap_VariableRateAxis_4e3dba35-58b9-487c-9fea-7bb31bae3c8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_4e3dba35-58b9-487c-9fea-7bb31bae3c8a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_4e3dba35-58b9-487c-9fea-7bb31bae3c8a" xlink:to="loc_us-gaap_VariableRateDomain_4e3dba35-58b9-487c-9fea-7bb31bae3c8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_17146d7d-f011-4d53-a90d-243ecd77eba8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_4e3dba35-58b9-487c-9fea-7bb31bae3c8a" xlink:to="loc_us-gaap_VariableRateDomain_17146d7d-f011-4d53-a90d-243ecd77eba8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_7064df7c-a32a-42e1-81f8-b595760af6ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d4688b45-2125-46ae-9863-11aa094186f0" xlink:to="loc_us-gaap_DebtInstrumentAxis_7064df7c-a32a-42e1-81f8-b595760af6ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7064df7c-a32a-42e1-81f8-b595760af6ce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_7064df7c-a32a-42e1-81f8-b595760af6ce" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7064df7c-a32a-42e1-81f8-b595760af6ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b481e9ef-c9c5-466f-970f-d9e989f030c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_7064df7c-a32a-42e1-81f8-b595760af6ce" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b481e9ef-c9c5-466f-970f-d9e989f030c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_126d79b4-60dc-4d55-b47f-5916cb0d6da6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d4688b45-2125-46ae-9863-11aa094186f0" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_126d79b4-60dc-4d55-b47f-5916cb0d6da6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_126d79b4-60dc-4d55-b47f-5916cb0d6da6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_126d79b4-60dc-4d55-b47f-5916cb0d6da6" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_126d79b4-60dc-4d55-b47f-5916cb0d6da6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ed25f3c0-14e0-4176-8c06-ca9fd64285a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_126d79b4-60dc-4d55-b47f-5916cb0d6da6" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ed25f3c0-14e0-4176-8c06-ca9fd64285a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_86d83b6f-7d67-4d7f-b033-e63f0768cf24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ed25f3c0-14e0-4176-8c06-ca9fd64285a5" xlink:to="loc_us-gaap_SecuredDebtMember_86d83b6f-7d67-4d7f-b033-e63f0768cf24" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_b32027bb-9280-4bf0-bb2d-e1ed6e9a516b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ed25f3c0-14e0-4176-8c06-ca9fd64285a5" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_b32027bb-9280-4bf0-bb2d-e1ed6e9a516b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_e05479b4-9128-4dbf-939b-1b4ad77c2503" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ed25f3c0-14e0-4176-8c06-ca9fd64285a5" xlink:to="loc_us-gaap_SeniorNotesMember_e05479b4-9128-4dbf-939b-1b4ad77c2503" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsSummaryOfCarryingAmountAndFairValueOfFinancialInstrumentsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#FairValueOfFinancialInstrumentsSummaryOfCarryingAmountAndFairValueOfFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsSummaryOfCarryingAmountAndFairValueOfFinancialInstrumentsDetails" xlink:type="extended" id="ie24efdb27c3b4ad5b67e6fc9787ef48b_FairValueOfFinancialInstrumentsSummaryOfCarryingAmountAndFairValueOfFinancialInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_4a0a991a-0860-498c-9c11-9e185cb7c31f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_0b4baa02-9a10-4dce-b783-a29f7647d8b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_4a0a991a-0860-498c-9c11-9e185cb7c31f" xlink:to="loc_us-gaap_LongTermDebtFairValue_0b4baa02-9a10-4dce-b783-a29f7647d8b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8b1ddfa1-6d26-4712-9f31-497ef0497123" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_4a0a991a-0860-498c-9c11-9e185cb7c31f" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8b1ddfa1-6d26-4712-9f31-497ef0497123" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_78ea2979-e46c-46c9-abe5-8297405ea267" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8b1ddfa1-6d26-4712-9f31-497ef0497123" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_78ea2979-e46c-46c9-abe5-8297405ea267" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_78ea2979-e46c-46c9-abe5-8297405ea267_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_78ea2979-e46c-46c9-abe5-8297405ea267" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_78ea2979-e46c-46c9-abe5-8297405ea267_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1ceeee86-6a25-4c95-9f75-70cce23e5cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_78ea2979-e46c-46c9-abe5-8297405ea267" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1ceeee86-6a25-4c95-9f75-70cce23e5cd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgagesPayableAndNotesPayableMember_a8d5a7db-9102-47de-8a2b-4871ccece35f" xlink:href="frt-20211231.xsd#frt_MortgagesPayableAndNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1ceeee86-6a25-4c95-9f75-70cce23e5cd1" xlink:to="loc_frt_MortgagesPayableAndNotesPayableMember_a8d5a7db-9102-47de-8a2b-4871ccece35f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SeniorNotesAndDebenturesMember_b54ba7c9-6a04-47fd-8265-55b6397282bc" xlink:href="frt-20211231.xsd#frt_SeniorNotesAndDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1ceeee86-6a25-4c95-9f75-70cce23e5cd1" xlink:to="loc_frt_SeniorNotesAndDebenturesMember_b54ba7c9-6a04-47fd-8265-55b6397282bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_7c0e0119-c787-49cd-9eb8-af56aabd1aa8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8b1ddfa1-6d26-4712-9f31-497ef0497123" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_7c0e0119-c787-49cd-9eb8-af56aabd1aa8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7c0e0119-c787-49cd-9eb8-af56aabd1aa8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_7c0e0119-c787-49cd-9eb8-af56aabd1aa8" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7c0e0119-c787-49cd-9eb8-af56aabd1aa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_b20fe937-c89e-43ac-80b1-158dd33c6d02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_7c0e0119-c787-49cd-9eb8-af56aabd1aa8" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_b20fe937-c89e-43ac-80b1-158dd33c6d02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8f41b0cd-fb00-40c8-8a7a-c978fd872dca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_b20fe937-c89e-43ac-80b1-158dd33c6d02" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8f41b0cd-fb00-40c8-8a7a-c978fd872dca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_c96d9e25-5633-4c92-a5d8-b500c95a19b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8f41b0cd-fb00-40c8-8a7a-c978fd872dca" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_c96d9e25-5633-4c92-a5d8-b500c95a19b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_38bafbfb-e011-4fcb-bcf4-a69f367ea7c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8f41b0cd-fb00-40c8-8a7a-c978fd872dca" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_38bafbfb-e011-4fcb-bcf4-a69f367ea7c4" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#FairValueOfFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsDetails" xlink:type="extended" id="ic5c860c84ec7418194b9a74dd3d7d439_FairValueOfFinancialInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfInterestRateDerivativesHeld_412bdd3f-69b4-435f-b131-71090517650c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfInterestRateDerivativesHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_NumberOfInterestRateDerivativesHeld_412bdd3f-69b4-435f-b131-71090517650c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_bf31f81f-6ee6-4d61-9286-0990c05199e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_bf31f81f-6ee6-4d61-9286-0990c05199e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_30e0b037-93dd-4d47-b015-2f2acead387b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_30e0b037-93dd-4d47-b015-2f2acead387b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_fa703c1f-2143-484a-ba30-dc2386fed9b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_fa703c1f-2143-484a-ba30-dc2386fed9b4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDerivativeLiabilities_1e517286-acd5-4401-bc05-9aa0f6dc907d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_IncreaseDecreaseInDerivativeLiabilities_1e517286-acd5-4401-bc05-9aa0f6dc907d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_d98cbc63-4d74-48c8-a4ea-c7182469299c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_d98cbc63-4d74-48c8-a4ea-c7182469299c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a21cb722-8e3d-4e4b-90a6-3d136da9e989" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a21cb722-8e3d-4e4b-90a6-3d136da9e989" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_cdd873fe-37fd-4140-8871-edafafe2a250" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_DerivativeLiabilities_cdd873fe-37fd-4140-8871-edafafe2a250" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_10f1df22-1d6e-4bf2-a71e-1bd4ab9d7a3d" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_edd15fcb-6441-4448-bbdf-f055438fbba0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_DebtInstrumentAxis_edd15fcb-6441-4448-bbdf-f055438fbba0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_edd15fcb-6441-4448-bbdf-f055438fbba0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_edd15fcb-6441-4448-bbdf-f055438fbba0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_edd15fcb-6441-4448-bbdf-f055438fbba0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_36f44e47-1d53-4980-979e-5a78dbbcfdd3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_edd15fcb-6441-4448-bbdf-f055438fbba0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_36f44e47-1d53-4980-979e-5a78dbbcfdd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_173de714-c46c-43b9-a426-6805b41d11c1" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_36f44e47-1d53-4980-979e-5a78dbbcfdd3" xlink:to="loc_frt_HobokenMember_173de714-c46c-43b9-a426-6805b41d11c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_585178bf-515a-4bfc-a266-63514bb31c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_36f44e47-1d53-4980-979e-5a78dbbcfdd3" xlink:to="loc_us-gaap_InterestRateSwapMember_585178bf-515a-4bfc-a266-63514bb31c4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_847a237d-06c0-4cf1-82f3-c280182db94a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_847a237d-06c0-4cf1-82f3-c280182db94a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_847a237d-06c0-4cf1-82f3-c280182db94a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_847a237d-06c0-4cf1-82f3-c280182db94a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_847a237d-06c0-4cf1-82f3-c280182db94a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_f397329e-edab-4560-aaa3-ef612dbe2216" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_847a237d-06c0-4cf1-82f3-c280182db94a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_f397329e-edab-4560-aaa3-ef612dbe2216" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_8027b810-d2e0-406e-ba00-aae1c02d5bb6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_f397329e-edab-4560-aaa3-ef612dbe2216" xlink:to="loc_us-gaap_SecuredDebtMember_8027b810-d2e0-406e-ba00-aae1c02d5bb6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_40af593d-d947-48ba-b8e3-a3a7d820315e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_40af593d-d947-48ba-b8e3-a3a7d820315e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_40af593d-d947-48ba-b8e3-a3a7d820315e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_40af593d-d947-48ba-b8e3-a3a7d820315e" xlink:to="loc_us-gaap_EquityComponentDomain_40af593d-d947-48ba-b8e3-a3a7d820315e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c8f36070-baf4-48c9-bd12-45f50cd11eea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_40af593d-d947-48ba-b8e3-a3a7d820315e" xlink:to="loc_us-gaap_EquityComponentDomain_c8f36070-baf4-48c9-bd12-45f50cd11eea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_52436084-d773-4a74-828b-0e6cdb5a1d11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c8f36070-baf4-48c9-bd12-45f50cd11eea" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_52436084-d773-4a74-828b-0e6cdb5a1d11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_527e859a-d531-4d71-94c5-ed68969f2bfc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_527e859a-d531-4d71-94c5-ed68969f2bfc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_527e859a-d531-4d71-94c5-ed68969f2bfc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_527e859a-d531-4d71-94c5-ed68969f2bfc" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_527e859a-d531-4d71-94c5-ed68969f2bfc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_ec641fbf-cb33-439e-85cb-82ed37a686e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_527e859a-d531-4d71-94c5-ed68969f2bfc" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_ec641fbf-cb33-439e-85cb-82ed37a686e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_3f905a0b-45b9-47c9-b667-d496357b8359" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_ec641fbf-cb33-439e-85cb-82ed37a686e3" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_3f905a0b-45b9-47c9-b667-d496357b8359" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4bb2a8a0-265e-474f-9936-7c4b324b4423" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4bb2a8a0-265e-474f-9936-7c4b324b4423" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4bb2a8a0-265e-474f-9936-7c4b324b4423_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4bb2a8a0-265e-474f-9936-7c4b324b4423" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4bb2a8a0-265e-474f-9936-7c4b324b4423_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4d54b51a-fcd2-4ec7-bae7-262d0b178aa9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4bb2a8a0-265e-474f-9936-7c4b324b4423" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4d54b51a-fcd2-4ec7-bae7-262d0b178aa9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6de909c2-14db-47aa-8156-0f364d8048ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4d54b51a-fcd2-4ec7-bae7-262d0b178aa9" xlink:to="loc_us-gaap_InterestRateSwapMember_6de909c2-14db-47aa-8156-0f364d8048ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_68a5e079-fbcf-46dd-b445-839ae31ddb06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_68a5e079-fbcf-46dd-b445-839ae31ddb06" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_68a5e079-fbcf-46dd-b445-839ae31ddb06_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_68a5e079-fbcf-46dd-b445-839ae31ddb06" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_68a5e079-fbcf-46dd-b445-839ae31ddb06_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_dcaa0394-9fd7-4457-8c1d-55bbd7d728de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_68a5e079-fbcf-46dd-b445-839ae31ddb06" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_dcaa0394-9fd7-4457-8c1d-55bbd7d728de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PrepaidexpensesandotherassetsMember_6039b635-a9d5-4df7-8313-21c35ad48a0e" xlink:href="frt-20211231.xsd#frt_PrepaidexpensesandotherassetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_dcaa0394-9fd7-4457-8c1d-55bbd7d728de" xlink:to="loc_frt_PrepaidexpensesandotherassetsMember_6039b635-a9d5-4df7-8313-21c35ad48a0e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2d0e0915-368f-4aa6-a290-791c3d8ceb1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_3135b0bb-7f18-4df4-ab28-a868f2ea4031" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2d0e0915-368f-4aa6-a290-791c3d8ceb1c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_2d0e0915-368f-4aa6-a290-791c3d8ceb1c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2d0e0915-368f-4aa6-a290-791c3d8ceb1c" xlink:to="loc_us-gaap_RelatedPartyDomain_2d0e0915-368f-4aa6-a290-791c3d8ceb1c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9b661a4b-2a02-4c36-b9ec-cb4c7d02d8f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2d0e0915-368f-4aa6-a290-791c3d8ceb1c" xlink:to="loc_us-gaap_RelatedPartyDomain_9b661a4b-2a02-4c36-b9ec-cb4c7d02d8f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_bc1f01db-5ad3-45f8-bf46-e004505b6253" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_9b661a4b-2a02-4c36-b9ec-cb4c7d02d8f0" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_bc1f01db-5ad3-45f8-bf46-e004505b6253" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueOnARecurringBasisDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#FairValueOfFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueOnARecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueOnARecurringBasisDetails" xlink:type="extended" id="ia260d194dd57481a8dcb3938e90252b7_FairValueOfFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueOnARecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_05552a37-4dad-4389-97d1-3b622457a61e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_a5f75b7d-4963-4e29-97f6-1b590af9ac68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_05552a37-4dad-4389-97d1-3b622457a61e" xlink:to="loc_us-gaap_DerivativeLiabilities_a5f75b7d-4963-4e29-97f6-1b590af9ac68" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_05552a37-4dad-4389-97d1-3b622457a61e" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_ed3653b6-f70c-492a-adc5-ed3307fc46a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_ed3653b6-f70c-492a-adc5-ed3307fc46a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ed3653b6-f70c-492a-adc5-ed3307fc46a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ed3653b6-f70c-492a-adc5-ed3307fc46a2" xlink:to="loc_us-gaap_EquityComponentDomain_ed3653b6-f70c-492a-adc5-ed3307fc46a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_bbafe8f4-5920-4414-ac49-d5967a3afe97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ed3653b6-f70c-492a-adc5-ed3307fc46a2" xlink:to="loc_us-gaap_EquityComponentDomain_bbafe8f4-5920-4414-ac49-d5967a3afe97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_41e15e72-29c3-4760-b5dc-065ba1b319d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_bbafe8f4-5920-4414-ac49-d5967a3afe97" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_41e15e72-29c3-4760-b5dc-065ba1b319d9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_04622449-dcf7-4d03-8949-8c67e127ae9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_04622449-dcf7-4d03-8949-8c67e127ae9b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_04622449-dcf7-4d03-8949-8c67e127ae9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_04622449-dcf7-4d03-8949-8c67e127ae9b" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_04622449-dcf7-4d03-8949-8c67e127ae9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_b9574fdf-1572-4fc8-a651-b748cc52eea4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_04622449-dcf7-4d03-8949-8c67e127ae9b" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_b9574fdf-1572-4fc8-a651-b748cc52eea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_fe9e11f8-004d-4427-8b1a-856d9fe490b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_b9574fdf-1572-4fc8-a651-b748cc52eea4" xlink:to="loc_us-gaap_InterestRateSwapMember_fe9e11f8-004d-4427-8b1a-856d9fe490b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27a1205b-f2c5-4436-96e4-657f310dfcc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27a1205b-f2c5-4436-96e4-657f310dfcc2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_27a1205b-f2c5-4436-96e4-657f310dfcc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27a1205b-f2c5-4436-96e4-657f310dfcc2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_27a1205b-f2c5-4436-96e4-657f310dfcc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_844d1af0-72e3-4ab6-9f7f-8b560bcc8003" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27a1205b-f2c5-4436-96e4-657f310dfcc2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_844d1af0-72e3-4ab6-9f7f-8b560bcc8003" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_4e10c877-f40a-4d31-8e2d-97f58bbfc976" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_844d1af0-72e3-4ab6-9f7f-8b560bcc8003" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_4e10c877-f40a-4d31-8e2d-97f58bbfc976" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_08521449-4d43-49fe-8c40-92780cef547e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_08521449-4d43-49fe-8c40-92780cef547e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_08521449-4d43-49fe-8c40-92780cef547e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_08521449-4d43-49fe-8c40-92780cef547e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_08521449-4d43-49fe-8c40-92780cef547e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53b1200a-6198-4dff-9175-824ef20ebd30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_08521449-4d43-49fe-8c40-92780cef547e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53b1200a-6198-4dff-9175-824ef20ebd30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_1ad7ea5f-b97b-4e3b-8d5a-eedb2980fcd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53b1200a-6198-4dff-9175-824ef20ebd30" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_1ad7ea5f-b97b-4e3b-8d5a-eedb2980fcd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_8f6f1307-afd0-408f-9d29-35d053936194" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53b1200a-6198-4dff-9175-824ef20ebd30" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_8f6f1307-afd0-408f-9d29-35d053936194" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_2a9468ca-71d3-4aaa-ba16-786cb02a1ede" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53b1200a-6198-4dff-9175-824ef20ebd30" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_2a9468ca-71d3-4aaa-ba16-786cb02a1ede" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_bc297e7d-a413-441a-a7a4-9712b03ca6c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fd4577b3-d1de-4732-ae09-141736e121bc" xlink:to="loc_us-gaap_DebtInstrumentAxis_bc297e7d-a413-441a-a7a4-9712b03ca6c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_bc297e7d-a413-441a-a7a4-9712b03ca6c0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_bc297e7d-a413-441a-a7a4-9712b03ca6c0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_bc297e7d-a413-441a-a7a4-9712b03ca6c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_15241e02-246e-4ef8-88d5-55ae355d6b79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_bc297e7d-a413-441a-a7a4-9712b03ca6c0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_15241e02-246e-4ef8-88d5-55ae355d6b79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6c070880-eed5-4270-9c7a-204da536257d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_15241e02-246e-4ef8-88d5-55ae355d6b79" xlink:to="loc_us-gaap_InterestRateSwapMember_6c070880-eed5-4270-9c7a-204da536257d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#CommitmentsandContingenciesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/CommitmentsandContingenciesDetails" xlink:type="extended" id="i09c9b9e2aff943b2963683aaad6f7c0d_CommitmentsandContingenciesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationReserve_46381e54-03d2-48c0-9dc5-156caf3d9efd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_LitigationReserve_46381e54-03d2-48c0-9dc5-156caf3d9efd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyAccrual_f7d7cf91-684b-4340-a04a-aacb66da9e07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductWarrantyAccrual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_ProductWarrantyAccrual_f7d7cf91-684b-4340-a04a-aacb66da9e07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyAccrualPayments_73bf8b47-6cc1-43dd-8fa1-a886797a9d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductWarrantyAccrualPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_ProductWarrantyAccrualPayments_73bf8b47-6cc1-43dd-8fa1-a886797a9d3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_11510641-88d4-4141-921f-a28fd7a8ba46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_11510641-88d4-4141-921f-a28fd7a8ba46" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligation_1a932b4f-03f6-4b70-b4c0-61a297417f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_ContractualObligation_1a932b4f-03f6-4b70-b4c0-61a297417f4a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PurchasePriceUnderOption_165c73d9-ebd4-45a8-a9e4-8376e289c004" xlink:href="frt-20211231.xsd#frt_PurchasePriceUnderOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_PurchasePriceUnderOption_165c73d9-ebd4-45a8-a9e4-8376e289c004" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OwnershipInterestOfOtherPartnerInPutOption_fc2a86c6-d516-4b77-8c7b-f4056f2627fb" xlink:href="frt-20211231.xsd#frt_OwnershipInterestOfOtherPartnerInPutOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_OwnershipInterestOfOtherPartnerInPutOption_fc2a86c6-d516-4b77-8c7b-f4056f2627fb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EstimatedLiabilityUponExerciseOfOption_8cc5211c-6b7e-4887-b091-31010cb5ab5f" xlink:href="frt-20211231.xsd#frt_EstimatedLiabilityUponExerciseOfOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_EstimatedLiabilityUponExerciseOfOption_8cc5211c-6b7e-4887-b091-31010cb5ab5f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NumberOfMembersWithPurchaseOptions_df1a16fa-0fab-4c04-9b19-8e9c1d3f8e0f" xlink:href="frt-20211231.xsd#frt_NumberOfMembersWithPurchaseOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_NumberOfMembersWithPurchaseOptions_df1a16fa-0fab-4c04-9b19-8e9c1d3f8e0f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnits_df196e44-6c32-42fe-866a-ff1f96715202" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_PartnersCapitalAccountUnits_df196e44-6c32-42fe-866a-ff1f96715202" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OperatingPartnershipUnitsFairValue_272d9f99-113a-4f8b-a055-3483b531670a" xlink:href="frt-20211231.xsd#frt_OperatingPartnershipUnitsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_OperatingPartnershipUnitsFairValue_272d9f99-113a-4f8b-a055-3483b531670a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CostsAssociatedWithLeaseBuyoutForAPropertySold_c305be25-d834-4ddf-8225-fb401c90e19b" xlink:href="frt-20211231.xsd#frt_CostsAssociatedWithLeaseBuyoutForAPropertySold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_CostsAssociatedWithLeaseBuyoutForAPropertySold_c305be25-d834-4ddf-8225-fb401c90e19b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionIndexedToIssuersEquityPercentageOfIndexedOwnershipInterest_8d54f9e5-1aa9-4b5d-926f-3686f7b1581a" xlink:href="frt-20211231.xsd#frt_OptionIndexedToIssuersEquityPercentageOfIndexedOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_frt_OptionIndexedToIssuersEquityPercentageOfIndexedOwnershipInterest_8d54f9e5-1aa9-4b5d-926f-3686f7b1581a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_e1ffbd58-d270-4926-98f5-9195f050406f" xlink:to="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ContractualObligationAxis_b845e8d0-b0bd-4e1e-81b5-4394691d3b56" xlink:href="frt-20211231.xsd#frt_ContractualObligationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_frt_ContractualObligationAxis_b845e8d0-b0bd-4e1e-81b5-4394691d3b56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ContractualObligationDomain_b845e8d0-b0bd-4e1e-81b5-4394691d3b56_default" xlink:href="frt-20211231.xsd#frt_ContractualObligationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ContractualObligationAxis_b845e8d0-b0bd-4e1e-81b5-4394691d3b56" xlink:to="loc_frt_ContractualObligationDomain_b845e8d0-b0bd-4e1e-81b5-4394691d3b56_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ContractualObligationDomain_3188da5b-ba42-4bfe-8a7a-f4780def229b" xlink:href="frt-20211231.xsd#frt_ContractualObligationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ContractualObligationAxis_b845e8d0-b0bd-4e1e-81b5-4394691d3b56" xlink:to="loc_frt_ContractualObligationDomain_3188da5b-ba42-4bfe-8a7a-f4780def229b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CapitalImprovementDevelopmentAndRedevelopmentProjectsMember_9acdb6b2-6b19-42c2-bf55-ffee29053503" xlink:href="frt-20211231.xsd#frt_CapitalImprovementDevelopmentAndRedevelopmentProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ContractualObligationDomain_3188da5b-ba42-4bfe-8a7a-f4780def229b" xlink:to="loc_frt_CapitalImprovementDevelopmentAndRedevelopmentProjectsMember_9acdb6b2-6b19-42c2-bf55-ffee29053503" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_5fe1a3f7-c50d-4751-a928-a867d51e6009" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_srt_CounterpartyNameAxis_5fe1a3f7-c50d-4751-a928-a867d51e6009" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5fe1a3f7-c50d-4751-a928-a867d51e6009_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_5fe1a3f7-c50d-4751-a928-a867d51e6009" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5fe1a3f7-c50d-4751-a928-a867d51e6009_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7a765551-c3b6-45f4-86d9-e68f7c238acd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_5fe1a3f7-c50d-4751-a928-a867d51e6009" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7a765551-c3b6-45f4-86d9-e68f7c238acd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MemberOneInPlazaElSegundoMember_4a863910-db51-46a7-a18e-19a8df53d156" xlink:href="frt-20211231.xsd#frt_MemberOneInPlazaElSegundoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7a765551-c3b6-45f4-86d9-e68f7c238acd" xlink:to="loc_frt_MemberOneInPlazaElSegundoMember_4a863910-db51-46a7-a18e-19a8df53d156" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MemberTwoInPlazaElSegundoMember_97b834a3-306b-478e-8114-df8cf0953ab3" xlink:href="frt-20211231.xsd#frt_MemberTwoInPlazaElSegundoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7a765551-c3b6-45f4-86d9-e68f7c238acd" xlink:to="loc_frt_MemberTwoInPlazaElSegundoMember_97b834a3-306b-478e-8114-df8cf0953ab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_b15793bb-6ccb-468a-a0ca-79f1bce95fc4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_srt_StatementScenarioAxis_b15793bb-6ccb-468a-a0ca-79f1bce95fc4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_b15793bb-6ccb-468a-a0ca-79f1bce95fc4_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_b15793bb-6ccb-468a-a0ca-79f1bce95fc4" xlink:to="loc_srt_ScenarioUnspecifiedDomain_b15793bb-6ccb-468a-a0ca-79f1bce95fc4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_35dcae71-9c94-471d-8ebe-d236877417ee" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_b15793bb-6ccb-468a-a0ca-79f1bce95fc4" xlink:to="loc_srt_ScenarioUnspecifiedDomain_35dcae71-9c94-471d-8ebe-d236877417ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_87ae114f-637f-4587-8628-47d9bc33a1d4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_35dcae71-9c94-471d-8ebe-d236877417ee" xlink:to="loc_srt_ScenarioForecastMember_87ae114f-637f-4587-8628-47d9bc33a1d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesAxis_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_us-gaap_RealEstatePropertiesAxis_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesDomain_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RealEstatePropertiesAxis_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610" xlink:to="loc_us-gaap_RealEstatePropertiesDomain_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstatePropertiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RealEstatePropertiesAxis_f4a700b4-7cc0-4e6e-a1e7-39fa558d7610" xlink:to="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MercerMallMember_a10e5d0f-01f9-4a1b-9cc3-8f819500b2bc" xlink:href="frt-20211231.xsd#frt_MercerMallMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_MercerMallMember_a10e5d0f-01f9-4a1b-9cc3-8f819500b2bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CongressionalPlazaMember_ee21d308-a5d1-4d13-83d5-a3354f1da4d8" xlink:href="frt-20211231.xsd#frt_CongressionalPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_CongressionalPlazaMember_ee21d308-a5d1-4d13-83d5-a3354f1da4d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MelvilleMallMember_981c8b06-bf79-45e4-8a96-19f7cb349bd5" xlink:href="frt-20211231.xsd#frt_MelvilleMallMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_MelvilleMallMember_981c8b06-bf79-45e4-8a96-19f7cb349bd5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaElSegundoMember_1a92b69e-c195-4602-93ad-50e57cf684e2" xlink:href="frt-20211231.xsd#frt_PlazaElSegundoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_PlazaElSegundoMember_1a92b69e-c195-4602-93ad-50e57cf684e2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TheGroveatShrewsburyMember_4ba43790-15d2-4706-b40c-b3138fa7a43d" xlink:href="frt-20211231.xsd#frt_TheGroveatShrewsburyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_TheGroveatShrewsburyMember_4ba43790-15d2-4706-b40c-b3138fa7a43d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Brook35Member_ef8b63e0-f52d-4c0b-be6e-2db5a48c0255" xlink:href="frt-20211231.xsd#frt_Brook35Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_Brook35Member_ef8b63e0-f52d-4c0b-be6e-2db5a48c0255" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GroveAtShrewsburyAndBrook35Member_4bd596fd-4205-466d-a0f3-b0749545ed37" xlink:href="frt-20211231.xsd#frt_GroveAtShrewsburyAndBrook35Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_GroveAtShrewsburyAndBrook35Member_4bd596fd-4205-466d-a0f3-b0749545ed37" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_c1825def-6d0d-4689-8c03-014420ac2d2e" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_HobokenMember_c1825def-6d0d-4689-8c03-014420ac2d2e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CamelbackColonnadeAndHiltonVillageMember_27821794-41b7-4c6b-ba07-eb70b0b13493" xlink:href="frt-20211231.xsd#frt_CamelbackColonnadeAndHiltonVillageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_CamelbackColonnadeAndHiltonVillageMember_27821794-41b7-4c6b-ba07-eb70b0b13493" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrossmontCenterMember_fb7e63d5-a9d9-4fa6-913f-e1e048a3eb25" xlink:href="frt-20211231.xsd#frt_GrossmontCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_21eb97c8-b81a-4be1-b8fd-dd3d9aeeb29c" xlink:to="loc_frt_GrossmontCenterMember_fb7e63d5-a9d9-4fa6-913f-e1e048a3eb25" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeAxis_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f" xlink:href="frt-20211231.xsd#frt_OptionByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_frt_OptionByTypeAxis_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeDomain_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f_default" xlink:href="frt-20211231.xsd#frt_OptionByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_OptionByTypeAxis_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f" xlink:to="loc_frt_OptionByTypeDomain_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OptionByTypeDomain_8a08f931-d048-4dea-bb34-c5e6a5513d92" xlink:href="frt-20211231.xsd#frt_OptionByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_OptionByTypeAxis_5dbcdaa7-8d14-4293-9c96-85d81ca4fa5f" xlink:to="loc_frt_OptionByTypeDomain_8a08f931-d048-4dea-bb34-c5e6a5513d92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PutOptionMember_c5f0d70f-3153-4b3b-a3fa-2c087873d967" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PutOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_OptionByTypeDomain_8a08f931-d048-4dea-bb34-c5e6a5513d92" xlink:to="loc_us-gaap_PutOptionMember_c5f0d70f-3153-4b3b-a3fa-2c087873d967" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_6796028c-46c9-4ea6-adde-390547ae1268" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_srt_RangeAxis_6796028c-46c9-4ea6-adde-390547ae1268" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6796028c-46c9-4ea6-adde-390547ae1268_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_6796028c-46c9-4ea6-adde-390547ae1268" xlink:to="loc_srt_RangeMember_6796028c-46c9-4ea6-adde-390547ae1268_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5cce20d8-ac28-4d01-ae8a-169bd8d2cfeb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_6796028c-46c9-4ea6-adde-390547ae1268" xlink:to="loc_srt_RangeMember_5cce20d8-ac28-4d01-ae8a-169bd8d2cfeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_db175cfd-5be8-4cae-9cb8-481124bc4b4c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5cce20d8-ac28-4d01-ae8a-169bd8d2cfeb" xlink:to="loc_srt_MinimumMember_db175cfd-5be8-4cae-9cb8-481124bc4b4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5df5817d-a29c-4d0a-9d11-df7a52d33145" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5cce20d8-ac28-4d01-ae8a-169bd8d2cfeb" xlink:to="loc_srt_MaximumMember_5df5817d-a29c-4d0a-9d11-df7a52d33145" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_58d23599-2d07-4275-a672-f3f9d0ccc8ad" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_6e4bcc34-9135-4ccb-ab68-3a4da0d078a5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_58d23599-2d07-4275-a672-f3f9d0ccc8ad" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58d23599-2d07-4275-a672-f3f9d0ccc8ad_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_58d23599-2d07-4275-a672-f3f9d0ccc8ad" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58d23599-2d07-4275-a672-f3f9d0ccc8ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_96cbff44-52b8-441e-9929-aed1685c0e6e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_58d23599-2d07-4275-a672-f3f9d0ccc8ad" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_96cbff44-52b8-441e-9929-aed1685c0e6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SanAntonioCenterMember_ee4b5037-941a-468f-bf8a-92afcbaa8f04" xlink:href="frt-20211231.xsd#frt_SanAntonioCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_96cbff44-52b8-441e-9929-aed1685c0e6e" xlink:to="loc_frt_SanAntonioCenterMember_ee4b5037-941a-468f-bf8a-92afcbaa8f04" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareholdersEquityDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ShareholdersEquityDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareholdersEquityDetails" xlink:type="extended" id="i7e68197b6bd54f8a9e01b0daf2dce952_ShareholdersEquityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_93378114-94a2-4404-87aa-80fced430436" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_93378114-94a2-4404-87aa-80fced430436" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_140ea4cb-8fc1-4f98-a959-a2d9ab0a460e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_140ea4cb-8fc1-4f98-a959-a2d9ab0a460e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_69f42eca-287e-47b7-bcf7-c31ea6fc814f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_69f42eca-287e-47b7-bcf7-c31ea6fc814f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_d0874b01-f42b-4079-b902-d659191a5650" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_d0874b01-f42b-4079-b902-d659191a5650" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_f68bedff-e954-44de-8759-9b39ca0d28bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_PreferredStockLiquidationPreference_f68bedff-e954-44de-8759-9b39ca0d28bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_7f71de07-2039-4c33-900e-b75e11479c39" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_7f71de07-2039-4c33-900e-b75e11479c39" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertiblePreferredStockConversionPricePerShare_d21e58e6-ab45-4a24-b14d-c0d5c766d404" xlink:href="frt-20211231.xsd#frt_ConvertiblePreferredStockConversionPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_frt_ConvertiblePreferredStockConversionPricePerShare_d21e58e6-ab45-4a24-b14d-c0d5c766d404" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AggregateOfferingPriceOfCommonShare_2f26c710-1bd9-4847-96a3-ee4194616a21" xlink:href="frt-20211231.xsd#frt_AggregateOfferingPriceOfCommonShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_frt_AggregateOfferingPriceOfCommonShare_2f26c710-1bd9-4847-96a3-ee4194616a21" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_d42b9f86-0771-45d9-bd9d-1a121e1123ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_d42b9f86-0771-45d9-bd9d-1a121e1123ca" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WeightedAveragePricePerCommonShare_90bfd175-f42e-4279-91ab-78b2e575899f" xlink:href="frt-20211231.xsd#frt_WeightedAveragePricePerCommonShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_frt_WeightedAveragePricePerCommonShare_90bfd175-f42e-4279-91ab-78b2e575899f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_48c0ca97-103d-4e84-8689-a7a861c6358c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_48c0ca97-103d-4e84-8689-a7a861c6358c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RemainingCapacityToIssue_8b03e2dd-992c-4a9b-808c-57e1879b0be7" xlink:href="frt-20211231.xsd#frt_RemainingCapacityToIssue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_frt_RemainingCapacityToIssue_8b03e2dd-992c-4a9b-808c-57e1879b0be7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractIndexedToIssuersEquityShares_309534f2-98d4-44ae-9a93-ca99f64183f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForwardContractIndexedToIssuersEquityShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_ForwardContractIndexedToIssuersEquityShares_309534f2-98d4-44ae-9a93-ca99f64183f1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_1134d208-b4bb-475c-a737-ed8e6877ed52" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9403a3ce-1643-4187-a49d-144a049d4fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9403a3ce-1643-4187-a49d-144a049d4fc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9403a3ce-1643-4187-a49d-144a049d4fc9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9403a3ce-1643-4187-a49d-144a049d4fc9" xlink:to="loc_us-gaap_EquityComponentDomain_9403a3ce-1643-4187-a49d-144a049d4fc9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_06d22966-4f7b-4f81-9b73-9cde346b20aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9403a3ce-1643-4187-a49d-144a049d4fc9" xlink:to="loc_us-gaap_EquityComponentDomain_06d22966-4f7b-4f81-9b73-9cde346b20aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_37f2a5ee-bd2e-44d9-9d6d-3e960d70da55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_06d22966-4f7b-4f81-9b73-9cde346b20aa" xlink:to="loc_us-gaap_PreferredStockMember_37f2a5ee-bd2e-44d9-9d6d-3e960d70da55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsByNameAxis_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredUnitsByNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:to="loc_us-gaap_PreferredUnitsByNameAxis_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsClassDomain_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredUnitsClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PreferredUnitsByNameAxis_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3" xlink:to="loc_us-gaap_PreferredUnitsClassDomain_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsClassDomain_e78dcc40-87a2-41ec-9f35-9b87eab1b35a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredUnitsClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PreferredUnitsByNameAxis_eb6d0575-c680-4c92-b3b1-ae0796f0cfc3" xlink:to="loc_us-gaap_PreferredUnitsClassDomain_e78dcc40-87a2-41ec-9f35-9b87eab1b35a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DepositorySharesMember_16947850-b4da-4ead-bb66-213a3a00fc33" xlink:href="frt-20211231.xsd#frt_DepositorySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PreferredUnitsClassDomain_e78dcc40-87a2-41ec-9f35-9b87eab1b35a" xlink:to="loc_frt_DepositorySharesMember_16947850-b4da-4ead-bb66-213a3a00fc33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_98148f5a-6ff5-42a1-9e7c-2a296d779a61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_98148f5a-6ff5-42a1-9e7c-2a296d779a61" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_98148f5a-6ff5-42a1-9e7c-2a296d779a61_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_98148f5a-6ff5-42a1-9e7c-2a296d779a61" xlink:to="loc_us-gaap_ClassOfStockDomain_98148f5a-6ff5-42a1-9e7c-2a296d779a61_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_b67268bb-1c71-4a82-9ef2-78902b69473e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_98148f5a-6ff5-42a1-9e7c-2a296d779a61" xlink:to="loc_us-gaap_ClassOfStockDomain_b67268bb-1c71-4a82-9ef2-78902b69473e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_8220ffcd-896a-47d6-a2ca-b73dcff00a83" xlink:href="frt-20211231.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_b67268bb-1c71-4a82-9ef2-78902b69473e" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_8220ffcd-896a-47d6-a2ca-b73dcff00a83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_ad3be1d5-fa5b-4bfb-a13c-00df27225d6a" xlink:href="frt-20211231.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_b67268bb-1c71-4a82-9ef2-78902b69473e" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_ad3be1d5-fa5b-4bfb-a13c-00df27225d6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_e901be35-590a-4c42-b22d-e4381fa9f8d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_e901be35-590a-4c42-b22d-e4381fa9f8d1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_e901be35-590a-4c42-b22d-e4381fa9f8d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_e901be35-590a-4c42-b22d-e4381fa9f8d1" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_e901be35-590a-4c42-b22d-e4381fa9f8d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c5f706c0-8377-4a20-bae9-6531662e5401" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_e901be35-590a-4c42-b22d-e4381fa9f8d1" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c5f706c0-8377-4a20-bae9-6531662e5401" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AtMarketEquityProgramMember_9a4c0c1c-c99a-4806-b88a-3242867448fb" xlink:href="frt-20211231.xsd#frt_AtMarketEquityProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c5f706c0-8377-4a20-bae9-6531662e5401" xlink:to="loc_frt_AtMarketEquityProgramMember_9a4c0c1c-c99a-4806-b88a-3242867448fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ForwardSalesContractsMember_25ebe434-0c3f-42a5-b271-6c319b2a3a62" xlink:href="frt-20211231.xsd#frt_ForwardSalesContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c5f706c0-8377-4a20-bae9-6531662e5401" xlink:to="loc_frt_ForwardSalesContractsMember_25ebe434-0c3f-42a5-b271-6c319b2a3a62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeAxis_ddc4fba1-3854-4b84-9732-30d2b65b58a7" xlink:href="frt-20211231.xsd#frt_StockIssuanceCostsByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_ad983031-b177-464e-b4cb-7cc7149e4e7c" xlink:to="loc_frt_StockIssuanceCostsByTypeAxis_ddc4fba1-3854-4b84-9732-30d2b65b58a7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeDomain_ddc4fba1-3854-4b84-9732-30d2b65b58a7_default" xlink:href="frt-20211231.xsd#frt_StockIssuanceCostsByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_StockIssuanceCostsByTypeAxis_ddc4fba1-3854-4b84-9732-30d2b65b58a7" xlink:to="loc_frt_StockIssuanceCostsByTypeDomain_ddc4fba1-3854-4b84-9732-30d2b65b58a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeDomain_66264bfd-0955-4b14-a079-c79967384be4" xlink:href="frt-20211231.xsd#frt_StockIssuanceCostsByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_StockIssuanceCostsByTypeAxis_ddc4fba1-3854-4b84-9732-30d2b65b58a7" xlink:to="loc_frt_StockIssuanceCostsByTypeDomain_66264bfd-0955-4b14-a079-c79967384be4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommissionsMember_18060e06-9633-468e-ace2-66ed18a15f73" xlink:href="frt-20211231.xsd#frt_CommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_StockIssuanceCostsByTypeDomain_66264bfd-0955-4b14-a079-c79967384be4" xlink:to="loc_frt_CommissionsMember_18060e06-9633-468e-ace2-66ed18a15f73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherOfferingCostsMember_7902adb3-2f3c-4098-865e-e0b788c853e3" xlink:href="frt-20211231.xsd#frt_OtherOfferingCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_StockIssuanceCostsByTypeDomain_66264bfd-0955-4b14-a079-c79967384be4" xlink:to="loc_frt_OtherOfferingCostsMember_7902adb3-2f3c-4098-865e-e0b788c853e3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/DividendsDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#DividendsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DividendsDetails" xlink:type="extended" id="idb566f018ce94626b6b88b9d4da4ff3f_DividendsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_f80164b6-e7be-4be5-8fd3-dc73a2bef002" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_f80164b6-e7be-4be5-8fd3-dc73a2bef002" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_f1d6b140-f0f2-43e0-8d75-f909b20e0fef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_f1d6b140-f0f2-43e0-8d75-f909b20e0fef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_3edcac48-5503-4d52-9ea1-b437155cd3f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_3edcac48-5503-4d52-9ea1-b437155cd3f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareDeclared_a9bd87f0-f5da-40f3-b48d-519e9d0af466" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_PreferredStockDividendsPerShareDeclared_a9bd87f0-f5da-40f3-b48d-519e9d0af466" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_8c4bc814-b1db-4429-93e1-f9f712c90042" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_8c4bc814-b1db-4429-93e1-f9f712c90042" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonStockOrdinaryDividendsPerShareCashPaid_fa35ca1d-0894-4fc1-b480-e214271001e7" xlink:href="frt-20211231.xsd#frt_CommonStockOrdinaryDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_frt_CommonStockOrdinaryDividendsPerShareCashPaid_fa35ca1d-0894-4fc1-b480-e214271001e7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonSharesCapitalGain_285060cb-0eef-4f4e-a614-94dfdb0380c6" xlink:href="frt-20211231.xsd#frt_CommonSharesCapitalGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_frt_CommonSharesCapitalGain_285060cb-0eef-4f4e-a614-94dfdb0380c6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonSharesReturnOfCapital_cd2e9ecc-1c6d-4cb5-82ae-def1db76d90b" xlink:href="frt-20211231.xsd#frt_CommonSharesReturnOfCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_frt_CommonSharesReturnOfCapital_cd2e9ecc-1c6d-4cb5-82ae-def1db76d90b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredStockOrdinaryDividendsPerShareCashPaid_0d10ac31-0ea8-40a7-b890-cf3aa7f37baf" xlink:href="frt-20211231.xsd#frt_PreferredStockOrdinaryDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_frt_PreferredStockOrdinaryDividendsPerShareCashPaid_0d10ac31-0ea8-40a7-b890-cf3aa7f37baf" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredSharesCapitalGain_7e490a32-1df2-44e4-92b7-1ae37d9c121b" xlink:href="frt-20211231.xsd#frt_PreferredSharesCapitalGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_frt_PreferredSharesCapitalGain_7e490a32-1df2-44e4-92b7-1ae37d9c121b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_99a9ec42-95b7-4f1a-876d-2277541be905" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_7ff860d1-7da7-4fff-b788-3c16c2c2fb5e" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_99a9ec42-95b7-4f1a-876d-2277541be905" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_15a1fcfc-699c-40ab-a2ee-ec5968df38f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_99a9ec42-95b7-4f1a-876d-2277541be905" xlink:to="loc_us-gaap_StatementClassOfStockAxis_15a1fcfc-699c-40ab-a2ee-ec5968df38f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_15a1fcfc-699c-40ab-a2ee-ec5968df38f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_15a1fcfc-699c-40ab-a2ee-ec5968df38f7" xlink:to="loc_us-gaap_ClassOfStockDomain_15a1fcfc-699c-40ab-a2ee-ec5968df38f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e178bf60-cd4d-4212-9fca-98ecce663162" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_15a1fcfc-699c-40ab-a2ee-ec5968df38f7" xlink:to="loc_us-gaap_ClassOfStockDomain_e178bf60-cd4d-4212-9fca-98ecce663162" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_e4a28050-5673-4dd7-86fb-1f3cef755b44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e178bf60-cd4d-4212-9fca-98ecce663162" xlink:to="loc_us-gaap_CommonStockMember_e4a28050-5673-4dd7-86fb-1f3cef755b44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_c049ee62-b3da-42d7-96c0-e4128b13859c" xlink:href="frt-20211231.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e178bf60-cd4d-4212-9fca-98ecce663162" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_c049ee62-b3da-42d7-96c0-e4128b13859c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_0bf93e1a-9ff3-4079-8491-24f9c7d27179" xlink:href="frt-20211231.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e178bf60-cd4d-4212-9fca-98ecce663162" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_0bf93e1a-9ff3-4079-8491-24f9c7d27179" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/OperatingLeasesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#OperatingLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/OperatingLeasesDetails" xlink:type="extended" id="i9fea50db4ef1445ab32d1828ad0d8352_OperatingLeasesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_1ffb2bf5-1cb0-4a8b-ae33-fb7f5e8b6a9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_1ffb2bf5-1cb0-4a8b-ae33-fb7f5e8b6a9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfStatesInWhichEntityOperates_9555044f-fc63-47fb-9625-a7dc4bc20318" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfStatesInWhichEntityOperates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_us-gaap_NumberOfStatesInWhichEntityOperates_9555044f-fc63-47fb-9625-a7dc4bc20318" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NumberOfLeases_5d213ba6-ec31-47c9-bfc8-f0e556a70b5f" xlink:href="frt-20211231.xsd#frt_NumberOfLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_frt_NumberOfLeases_5d213ba6-ec31-47c9-bfc8-f0e556a70b5f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PercentOfAnnualizedBaseRentMaximum_f2cb2184-58c2-48cd-9f8f-79bf95fcf26b" xlink:href="frt-20211231.xsd#frt_PercentOfAnnualizedBaseRentMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_frt_PercentOfAnnualizedBaseRentMaximum_f2cb2184-58c2-48cd-9f8f-79bf95fcf26b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OperatingLeaseTerm_092025f6-714b-4c68-9682-afc50ea2c3b9" xlink:href="frt-20211231.xsd#frt_OperatingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_frt_OperatingLeaseTerm_092025f6-714b-4c68-9682-afc50ea2c3b9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_0e547074-6cf3-4b3b-b7b5-012d8e45db61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_0e547074-6cf3-4b3b-b7b5-012d8e45db61" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_7adc417f-49cc-4729-9337-3d72a0d6799f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_7adc417f-49cc-4729-9337-3d72a0d6799f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_a6abfe51-9220-4a0d-b7d3-f1da1c970d31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_a6abfe51-9220-4a0d-b7d3-f1da1c970d31" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_bd181841-b147-4fe9-a111-8e5ce0438f54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_bd181841-b147-4fe9-a111-8e5ce0438f54" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_208b7d7f-b291-4e8b-a0ea-2a8249b55e41" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_208b7d7f-b291-4e8b-a0ea-2a8249b55e41" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_0d940633-168d-42dc-a2fb-81ae12e69695" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_0d940633-168d-42dc-a2fb-81ae12e69695" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_27303efb-79a4-48ef-8aa7-2f390bbdc58d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_f52841b9-4de1-4c77-b93f-c97160a0795a" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_27303efb-79a4-48ef-8aa7-2f390bbdc58d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_a66bcf0c-60cb-466f-94a1-76736a43d483" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_0f534c69-7940-4bc7-812a-12099e60efb5" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_a66bcf0c-60cb-466f-94a1-76736a43d483" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_64bcb0df-8e42-47d7-8bf5-3c761628c8bd" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsByPropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_a66bcf0c-60cb-466f-94a1-76736a43d483" xlink:to="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_64bcb0df-8e42-47d7-8bf5-3c761628c8bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsPropertyTypeDomain_64bcb0df-8e42-47d7-8bf5-3c761628c8bd_default" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsPropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_64bcb0df-8e42-47d7-8bf5-3c761628c8bd" xlink:to="loc_frt_RealEstateInvestmentsPropertyTypeDomain_64bcb0df-8e42-47d7-8bf5-3c761628c8bd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RealEstateInvestmentsPropertyTypeDomain_59780cfd-60ac-44f0-a7f2-4812ab2a8315" xlink:href="frt-20211231.xsd#frt_RealEstateInvestmentsPropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_RealEstateInvestmentsByPropertyTypeAxis_64bcb0df-8e42-47d7-8bf5-3c761628c8bd" xlink:to="loc_frt_RealEstateInvestmentsPropertyTypeDomain_59780cfd-60ac-44f0-a7f2-4812ab2a8315" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_6a1a40e4-16ad-48c3-8271-035f550534b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_RealEstateInvestmentsPropertyTypeDomain_59780cfd-60ac-44f0-a7f2-4812ab2a8315" xlink:to="loc_us-gaap_CommercialRealEstateMember_6a1a40e4-16ad-48c3-8271-035f550534b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_9b170db2-acda-4bea-b633-f40663e18ca7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_RealEstateInvestmentsPropertyTypeDomain_59780cfd-60ac-44f0-a7f2-4812ab2a8315" xlink:to="loc_us-gaap_ResidentialRealEstateMember_9b170db2-acda-4bea-b633-f40663e18ca7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_a66bcf0c-60cb-466f-94a1-76736a43d483" xlink:to="loc_srt_RangeAxis_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af" xlink:to="loc_srt_RangeMember_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4e343076-2273-4f51-a749-695366c7502d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bcffe24c-e0bb-4a1d-a98a-1e77b3a475af" xlink:to="loc_srt_RangeMember_4e343076-2273-4f51-a749-695366c7502d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_77c96278-ac26-4515-a96e-300333e25cdf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4e343076-2273-4f51-a749-695366c7502d" xlink:to="loc_srt_MinimumMember_77c96278-ac26-4515-a96e-300333e25cdf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3cca97e3-ae0b-4a40-b407-66a8cfcd19da" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4e343076-2273-4f51-a749-695366c7502d" xlink:to="loc_srt_MaximumMember_3cca97e3-ae0b-4a40-b407-66a8cfcd19da" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ComponentsofRentalExpenseComponentsOfRentalExpensesDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ComponentsofRentalExpenseComponentsOfRentalExpensesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ComponentsofRentalExpenseComponentsOfRentalExpensesDetails" xlink:type="extended" id="iee8d3f487d624ef2927ba21c5066f4e4_ComponentsofRentalExpenseComponentsOfRentalExpensesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_e2dc9622-6a5c-4721-b9c7-88d137f5cbe9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnTerminationOfLease_c1af2582-cc7b-4640-b2b9-cc0f24c943f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnTerminationOfLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e2dc9622-6a5c-4721-b9c7-88d137f5cbe9" xlink:to="loc_us-gaap_GainLossOnTerminationOfLease_c1af2582-cc7b-4640-b2b9-cc0f24c943f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_ae34cc48-0346-4818-951d-6164410628b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_e2dc9622-6a5c-4721-b9c7-88d137f5cbe9" xlink:to="loc_us-gaap_StatementTable_ae34cc48-0346-4818-951d-6164410628b1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_05a55d09-c29f-4bad-9351-f65d24cbee48" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_ae34cc48-0346-4818-951d-6164410628b1" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_05a55d09-c29f-4bad-9351-f65d24cbee48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_05a55d09-c29f-4bad-9351-f65d24cbee48_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_05a55d09-c29f-4bad-9351-f65d24cbee48" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_05a55d09-c29f-4bad-9351-f65d24cbee48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_e6346441-e712-4ce4-8cd9-e6f7529129a8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_05a55d09-c29f-4bad-9351-f65d24cbee48" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_e6346441-e712-4ce4-8cd9-e6f7529129a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AssemblySquareMarketplaceMember_61c1ff83-06ae-492c-b559-53b55c86bbbd" xlink:href="frt-20211231.xsd#frt_AssemblySquareMarketplaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_e6346441-e712-4ce4-8cd9-e6f7529129a8" xlink:to="loc_frt_AssemblySquareMarketplaceMember_61c1ff83-06ae-492c-b559-53b55c86bbbd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareBasedCompensationPlansRestrictedShareActivityDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ShareBasedCompensationPlansRestrictedShareActivityDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareBasedCompensationPlansRestrictedShareActivityDetails" xlink:type="extended" id="ifa0429ab64174e81b188adf956876c45_ShareBasedCompensationPlansRestrictedShareActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_eb360c44-2f00-4e50-a60d-fea047daaa9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_eb360c44-2f00-4e50-a60d-fea047daaa9b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_891af361-8bfc-4e6f-b6b4-d48e6ae7d486" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_891af361-8bfc-4e6f-b6b4-d48e6ae7d486" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0afd7b32-9973-4e9c-a36a-bc0f4336d0cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0afd7b32-9973-4e9c-a36a-bc0f4336d0cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4321a96d-2bc9-45c8-ad53-d476cafe0638" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4321a96d-2bc9-45c8-ad53-d476cafe0638" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5a787777-50ce-4695-bad2-f28a4078fed1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5a787777-50ce-4695-bad2-f28a4078fed1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_15e1fa1e-2723-4660-87a3-a8f80bbb2fcb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_b7c44c97-3e5c-493c-a9e0-06c97cc2bc6f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_b7c44c97-3e5c-493c-a9e0-06c97cc2bc6f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_59211984-9b53-43db-916c-3508fbe84566" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_59211984-9b53-43db-916c-3508fbe84566" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_cfdb688f-327c-4203-b4e2-5142e216a769" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_cfdb688f-327c-4203-b4e2-5142e216a769" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_6f25f884-f507-4127-9df7-4e9243a8131b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4896d4c3-5429-4a63-bdd4-744b1ba536b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_6f25f884-f507-4127-9df7-4e9243a8131b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0bf1e191-b9b8-41d0-a5fe-31e24e8d568b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1744c5c5-dc6d-4539-a44e-b424a011d3d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8a3d5822-0394-4777-9312-edc176285682" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_eb360c44-2f00-4e50-a60d-fea047daaa9b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8a3d5822-0394-4777-9312-edc176285682" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_1a7119be-68ca-4e29-97c6-5410ad46eb7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8a3d5822-0394-4777-9312-edc176285682" xlink:to="loc_us-gaap_AwardTypeAxis_1a7119be-68ca-4e29-97c6-5410ad46eb7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1a7119be-68ca-4e29-97c6-5410ad46eb7b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_1a7119be-68ca-4e29-97c6-5410ad46eb7b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1a7119be-68ca-4e29-97c6-5410ad46eb7b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_176851cb-5f94-485d-876b-91771c19ad63" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_1a7119be-68ca-4e29-97c6-5410ad46eb7b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_176851cb-5f94-485d-876b-91771c19ad63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_0bfcb8d1-0a11-4c43-9949-9a4d6996195a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_176851cb-5f94-485d-876b-91771c19ad63" xlink:to="loc_us-gaap_RestrictedStockMember_0bfcb8d1-0a11-4c43-9949-9a4d6996195a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareBasedCompensationPlansRestrictedStockUnitsActivityDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ShareBasedCompensationPlansRestrictedStockUnitsActivityDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareBasedCompensationPlansRestrictedStockUnitsActivityDetails" xlink:type="extended" id="ia5f00b1fed9d4b40abed4294ffa6b4a0_ShareBasedCompensationPlansRestrictedStockUnitsActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_38b55757-12fa-463b-bdff-35c8d984d809" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_38b55757-12fa-463b-bdff-35c8d984d809" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_df814685-b1d3-48d6-a49f-b80830611db2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_df814685-b1d3-48d6-a49f-b80830611db2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3e153862-058b-45ea-b8c6-7897c1a77380" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3e153862-058b-45ea-b8c6-7897c1a77380" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_98a867ac-be8f-4e12-90e4-dc3f78f61dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_98a867ac-be8f-4e12-90e4-dc3f78f61dbd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_f551cd06-29d3-4261-a65b-bd5b2f9bc661" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_f551cd06-29d3-4261-a65b-bd5b2f9bc661" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_970803af-0b55-4101-9462-a7359d94a1bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_5d616d6c-370e-4036-9542-cf9c97d9010d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_5d616d6c-370e-4036-9542-cf9c97d9010d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_051772c5-ad09-43df-8f63-0a144251fe0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_051772c5-ad09-43df-8f63-0a144251fe0a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_e98d5622-fd28-44d1-b1b1-01d3fb4e2e74" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_e98d5622-fd28-44d1-b1b1-01d3fb4e2e74" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_e7d1c34c-0a57-43ee-90fd-30d447d41368" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_38d12485-89f5-4a32-a531-b187a70a1982" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_e7d1c34c-0a57-43ee-90fd-30d447d41368" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_12540473-50ac-4d78-aa30-98c6a3932f8f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0d20caa0-52c2-48f0-b9ef-88352aff33c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_38b55757-12fa-463b-bdff-35c8d984d809" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0d20caa0-52c2-48f0-b9ef-88352aff33c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a89f859b-4ac8-4347-8d3c-9971c35fc1c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0d20caa0-52c2-48f0-b9ef-88352aff33c4" xlink:to="loc_us-gaap_AwardTypeAxis_a89f859b-4ac8-4347-8d3c-9971c35fc1c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a89f859b-4ac8-4347-8d3c-9971c35fc1c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a89f859b-4ac8-4347-8d3c-9971c35fc1c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a89f859b-4ac8-4347-8d3c-9971c35fc1c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_28fed8a1-969e-4221-8d1a-53f79ac45e24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a89f859b-4ac8-4347-8d3c-9971c35fc1c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_28fed8a1-969e-4221-8d1a-53f79ac45e24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_bc01297a-e294-4635-b2a6-3c8909a06144" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_28fed8a1-969e-4221-8d1a-53f79ac45e24" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_bc01297a-e294-4635-b2a6-3c8909a06144" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_dbfbb705-ccba-44ef-a775-cbce0cfe6707" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0d20caa0-52c2-48f0-b9ef-88352aff33c4" xlink:to="loc_srt_TitleOfIndividualAxis_dbfbb705-ccba-44ef-a775-cbce0cfe6707" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_dbfbb705-ccba-44ef-a775-cbce0cfe6707_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_dbfbb705-ccba-44ef-a775-cbce0cfe6707" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_dbfbb705-ccba-44ef-a775-cbce0cfe6707_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ae196782-e927-4973-816f-bed30a8fad84" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_dbfbb705-ccba-44ef-a775-cbce0cfe6707" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ae196782-e927-4973-816f-bed30a8fad84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OfficerMember_f9a4bec6-f11c-4537-b6c0-5c5772b6e013" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ae196782-e927-4973-816f-bed30a8fad84" xlink:to="loc_srt_OfficerMember_f9a4bec6-f11c-4537-b6c0-5c5772b6e013" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareBasedCompensationPlansCommonSharesAwardedUnderVariousCompensationPlansDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ShareBasedCompensationPlansCommonSharesAwardedUnderVariousCompensationPlansDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareBasedCompensationPlansCommonSharesAwardedUnderVariousCompensationPlansDetails" xlink:type="extended" id="i98d47b44f13a44239b872310a80fcad6_ShareBasedCompensationPlansCommonSharesAwardedUnderVariousCompensationPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_232b1663-0d00-4919-b5c0-dd9419be64bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_51e2f68e-c162-4787-9665-f5a0f29882a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_232b1663-0d00-4919-b5c0-dd9419be64bb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_51e2f68e-c162-4787-9665-f5a0f29882a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_23a1a02a-4062-4f53-8723-f11ed6dcb31c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_232b1663-0d00-4919-b5c0-dd9419be64bb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_23a1a02a-4062-4f53-8723-f11ed6dcb31c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6215742a-8f0f-4bea-8acc-e9dbcc4d1a28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_232b1663-0d00-4919-b5c0-dd9419be64bb" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6215742a-8f0f-4bea-8acc-e9dbcc4d1a28" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6215742a-8f0f-4bea-8acc-e9dbcc4d1a28" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_36e81d89-b888-407f-b2bc-c0af7349964d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_bdccedc4-44e7-4602-8bf7-04e32cbbf7ea" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_36e81d89-b888-407f-b2bc-c0af7349964d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_5e7337c0-c682-4365-8330-951514833d83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_36e81d89-b888-407f-b2bc-c0af7349964d" xlink:to="loc_us-gaap_SubsequentEventMember_5e7337c0-c682-4365-8330-951514833d83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_0bff0e13-7126-4332-8036-1dc1fc274d46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6215742a-8f0f-4bea-8acc-e9dbcc4d1a28" xlink:to="loc_us-gaap_AwardTypeAxis_0bff0e13-7126-4332-8036-1dc1fc274d46" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0bff0e13-7126-4332-8036-1dc1fc274d46_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_0bff0e13-7126-4332-8036-1dc1fc274d46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0bff0e13-7126-4332-8036-1dc1fc274d46_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a414943d-0d2d-463e-a34a-69383f2a2419" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_0bff0e13-7126-4332-8036-1dc1fc274d46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a414943d-0d2d-463e-a34a-69383f2a2419" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_e8a17420-4413-4d67-a9f2-e1e1d2f57858" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a414943d-0d2d-463e-a34a-69383f2a2419" xlink:to="loc_us-gaap_RestrictedStockMember_e8a17420-4413-4d67-a9f2-e1e1d2f57858" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_91d3425d-52e9-454d-8419-36a2c8d5d9fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a414943d-0d2d-463e-a34a-69383f2a2419" xlink:to="loc_us-gaap_EmployeeStockOptionMember_91d3425d-52e9-454d-8419-36a2c8d5d9fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_37c7ff3d-8d44-44da-8d95-0b179fc55a27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a414943d-0d2d-463e-a34a-69383f2a2419" xlink:to="loc_us-gaap_StockCompensationPlanMember_37c7ff3d-8d44-44da-8d95-0b179fc55a27" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6215742a-8f0f-4bea-8acc-e9dbcc4d1a28" xlink:to="loc_srt_RangeAxis_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d" xlink:to="loc_srt_RangeMember_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6beaa59d-a875-44d2-b316-3baac7a9ed09" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_66c61a5e-c81d-4bd4-9b5a-31d173c5ab4d" xlink:to="loc_srt_RangeMember_6beaa59d-a875-44d2-b316-3baac7a9ed09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_5e6ed652-4356-42cd-bcb1-74efdff66df3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6beaa59d-a875-44d2-b316-3baac7a9ed09" xlink:to="loc_srt_MinimumMember_5e6ed652-4356-42cd-bcb1-74efdff66df3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6290e5c7-e16a-4379-9e5c-c33c36cf365a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6beaa59d-a875-44d2-b316-3baac7a9ed09" xlink:to="loc_srt_MaximumMember_6290e5c7-e16a-4379-9e5c-c33c36cf365a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareBasedCompensationPlansNarrativeDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ShareBasedCompensationPlansNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareBasedCompensationPlansNarrativeDetails" xlink:type="extended" id="i5c9aeb37b18a4e2dad9129c46f5a397e_ShareBasedCompensationPlansNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_813dc1a2-6a76-4d65-bade-77ce0b298708" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_813dc1a2-6a76-4d65-bade-77ce0b298708" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_acbd052f-8725-4a24-acf2-3a76478c5b84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_acbd052f-8725-4a24-acf2-3a76478c5b84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_0e0f0d73-9c76-4b49-b690-77eedfc7d551" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_0e0f0d73-9c76-4b49-b690-77eedfc7d551" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_880eda0e-3f1c-4e2a-8f64-5e74318fbd6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_880eda0e-3f1c-4e2a-8f64-5e74318fbd6a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_33d6f272-2c52-4603-a763-2cc957fb734f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_33d6f272-2c52-4603-a763-2cc957fb734f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_efb37fd2-5901-4d48-a37a-4efb8013ae6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_efb37fd2-5901-4d48-a37a-4efb8013ae6d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_c254369b-393b-44ae-84df-8f8926b47f71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_c254369b-393b-44ae-84df-8f8926b47f71" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2a4a0906-a293-46d8-8d9f-0e5cab259042" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2a4a0906-a293-46d8-8d9f-0e5cab259042" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_a0a19d92-a884-4e4f-8180-44877d1a0136" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_a0a19d92-a884-4e4f-8180-44877d1a0136" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_f1a8cc93-4be0-43f1-a0fa-203913786049" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_f1a8cc93-4be0-43f1-a0fa-203913786049" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognitionYears_5f657d6d-7039-433b-8383-2dc8a67c0869" xlink:href="frt-20211231.xsd#frt_ShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognitionYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_frt_ShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognitionYears_5f657d6d-7039-433b-8383-2dc8a67c0869" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e27e3bef-25ab-4116-be02-491116c2ea13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e27e3bef-25ab-4116-be02-491116c2ea13" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14740a7e-9b77-442d-a5d6-a33a2e5188ac" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_adae9bd5-b1f8-4634-b0a7-eb6798c054d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:to="loc_us-gaap_AwardTypeAxis_adae9bd5-b1f8-4634-b0a7-eb6798c054d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_adae9bd5-b1f8-4634-b0a7-eb6798c054d7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_adae9bd5-b1f8-4634-b0a7-eb6798c054d7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_adae9bd5-b1f8-4634-b0a7-eb6798c054d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_adae9bd5-b1f8-4634-b0a7-eb6798c054d7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_86ab36bb-780d-4ea7-9a99-2747fdc9727a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:to="loc_us-gaap_RestrictedStockMember_86ab36bb-780d-4ea7-9a99-2747fdc9727a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_c03cc9d1-ddc0-44f1-8cb4-a1ce2c2c9dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:to="loc_us-gaap_StockCompensationPlanMember_c03cc9d1-ddc0-44f1-8cb4-a1ce2c2c9dfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_b8cca6ad-a0b6-4169-8959-b1b296fa10a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:to="loc_us-gaap_EmployeeStockOptionMember_b8cca6ad-a0b6-4169-8959-b1b296fa10a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_e7ffced8-9ad0-4f6b-a6fb-ab79ea9a6b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1718ac31-f43c-4e33-a072-3a51a2ed59c0" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_e7ffced8-9ad0-4f6b-a6fb-ab79ea9a6b8d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_57f0a321-6228-457c-920f-8a5786c5aaf8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:to="loc_us-gaap_PlanNameAxis_57f0a321-6228-457c-920f-8a5786c5aaf8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_57f0a321-6228-457c-920f-8a5786c5aaf8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_57f0a321-6228-457c-920f-8a5786c5aaf8" xlink:to="loc_us-gaap_PlanNameDomain_57f0a321-6228-457c-920f-8a5786c5aaf8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_43d6d93d-1468-4976-ae19-45902e1372ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_57f0a321-6228-457c-920f-8a5786c5aaf8" xlink:to="loc_us-gaap_PlanNameDomain_43d6d93d-1468-4976-ae19-45902e1372ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PerformanceIncentivePlan2020Member_b1801614-88de-4d43-a046-14424d87bc15" xlink:href="frt-20211231.xsd#frt_PerformanceIncentivePlan2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_43d6d93d-1468-4976-ae19-45902e1372ec" xlink:to="loc_frt_PerformanceIncentivePlan2020Member_b1801614-88de-4d43-a046-14424d87bc15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PerformanceIncentivePlan2010Member_58f29fda-2c68-4b4a-8c18-3bdaf4c13134" xlink:href="frt-20211231.xsd#frt_PerformanceIncentivePlan2010Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_43d6d93d-1468-4976-ae19-45902e1372ec" xlink:to="loc_frt_PerformanceIncentivePlan2010Member_58f29fda-2c68-4b4a-8c18-3bdaf4c13134" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4661092e-9433-49ec-92ce-376df8414130" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:to="loc_srt_RangeAxis_4661092e-9433-49ec-92ce-376df8414130" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4661092e-9433-49ec-92ce-376df8414130_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4661092e-9433-49ec-92ce-376df8414130" xlink:to="loc_srt_RangeMember_4661092e-9433-49ec-92ce-376df8414130_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9546ae0e-11c2-4258-9029-962cac9af418" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4661092e-9433-49ec-92ce-376df8414130" xlink:to="loc_srt_RangeMember_9546ae0e-11c2-4258-9029-962cac9af418" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_72cb689c-72ca-4cf7-b4c1-0ebcc9640b57" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9546ae0e-11c2-4258-9029-962cac9af418" xlink:to="loc_srt_MinimumMember_72cb689c-72ca-4cf7-b4c1-0ebcc9640b57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_beae9121-341d-4179-aa24-4e61c903e628" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9546ae0e-11c2-4258-9029-962cac9af418" xlink:to="loc_srt_MaximumMember_beae9121-341d-4179-aa24-4e61c903e628" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_fed05b99-46a6-4f1d-9788-1874e186ef5d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_10602d8e-37fa-4be8-bcfa-e44b492c8872" xlink:to="loc_srt_TitleOfIndividualAxis_fed05b99-46a6-4f1d-9788-1874e186ef5d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_fed05b99-46a6-4f1d-9788-1874e186ef5d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_fed05b99-46a6-4f1d-9788-1874e186ef5d" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_fed05b99-46a6-4f1d-9788-1874e186ef5d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_339f7442-e958-4b97-bc4e-0bb6ce928ee2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_fed05b99-46a6-4f1d-9788-1874e186ef5d" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_339f7442-e958-4b97-bc4e-0bb6ce928ee2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OfficerMember_513f1f65-477f-4935-bcf1-0660d18feb61" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_339f7442-e958-4b97-bc4e-0bb6ce928ee2" xlink:to="loc_srt_OfficerMember_513f1f65-477f-4935-bcf1-0660d18feb61" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SavingsandRetirementPlansDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SavingsandRetirementPlansDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SavingsandRetirementPlansDetails" xlink:type="extended" id="i19277c22a2094bba9015e8c0b7c38f6a_SavingsandRetirementPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount_c22f87cf-f78d-4404-a4e0-5847e0c9173d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount_c22f87cf-f78d-4404-a4e0-5847e0c9173d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DeferredCompensationArrangementWithIndividualEmployerContributionPerEmployeeMatchingPercent_a8b65144-df39-47e7-92a7-3294ee648b8f" xlink:href="frt-20211231.xsd#frt_DeferredCompensationArrangementWithIndividualEmployerContributionPerEmployeeMatchingPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_frt_DeferredCompensationArrangementWithIndividualEmployerContributionPerEmployeeMatchingPercent_a8b65144-df39-47e7-92a7-3294ee648b8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0ba8c18a-50af-4e8d-ae70-172bfdffc291" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0ba8c18a-50af-4e8d-ae70-172bfdffc291" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer_3f5137d4-a96f-417a-b66e-1da383c5d2e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer_3f5137d4-a96f-417a-b66e-1da383c5d2e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability_4a598a99-005d-4724-9f49-82478bd916d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability_4a598a99-005d-4724-9f49-82478bd916d3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_c36343b4-b340-4cf3-8c9f-5c0688645b94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_6028519f-79f1-45c1-9b37-5b9e99b29352" xlink:to="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_c36343b4-b340-4cf3-8c9f-5c0688645b94" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_c36343b4-b340-4cf3-8c9f-5c0688645b94" xlink:to="loc_srt_RangeAxis_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8" xlink:to="loc_srt_RangeMember_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bba9100b-96e4-473e-96ba-6b03d606844b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e5d8ec64-1c79-41e2-b163-0b4e0ef0fee8" xlink:to="loc_srt_RangeMember_bba9100b-96e4-473e-96ba-6b03d606844b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_61a75753-9ac3-42a8-a3ce-9db6a1eecf73" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_bba9100b-96e4-473e-96ba-6b03d606844b" xlink:to="loc_srt_MaximumMember_61a75753-9ac3-42a8-a3ce-9db6a1eecf73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis_cb70119f-6270-44e5-ab4d-c0b2a0dac39e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_c36343b4-b340-4cf3-8c9f-5c0688645b94" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis_cb70119f-6270-44e5-ab4d-c0b2a0dac39e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain_cb70119f-6270-44e5-ab4d-c0b2a0dac39e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis_cb70119f-6270-44e5-ab4d-c0b2a0dac39e" xlink:to="loc_us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain_cb70119f-6270-44e5-ab4d-c0b2a0dac39e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain_3a2c529f-410f-4166-9411-683992900a11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis_cb70119f-6270-44e5-ab4d-c0b2a0dac39e" xlink:to="loc_us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain_3a2c529f-410f-4166-9411-683992900a11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualByTypeOfCompensationPensionAndOtherPostretirementBenefitsMember_09073c4c-a0fd-452e-aeec-9dd7f78f8b70" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualByTypeOfCompensationPensionAndOtherPostretirementBenefitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherPostretirementBenefitsIndividualContractsTypeOfDeferredCompensationDomain_3a2c529f-410f-4166-9411-683992900a11" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualByTypeOfCompensationPensionAndOtherPostretirementBenefitsMember_09073c4c-a0fd-452e-aeec-9dd7f78f8b70" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/EarningsPerShareNarrativeDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#EarningsPerShareNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/EarningsPerShareNarrativeDetails" xlink:type="extended" id="i54517865469b4d539973c84889a32382_EarningsPerShareNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01195fd6-980b-4c7f-968f-ec6dc12cd97b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights_78ab27b7-1dd5-48d1-86be-5c169258f934" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01195fd6-980b-4c7f-968f-ec6dc12cd97b" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights_78ab27b7-1dd5-48d1-86be-5c169258f934" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_be8e1fcf-40c9-4f89-b564-15a550ca6d82" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01195fd6-980b-4c7f-968f-ec6dc12cd97b" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_be8e1fcf-40c9-4f89-b564-15a550ca6d82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_770828fd-4653-459b-b6c9-034463f73429" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01195fd6-980b-4c7f-968f-ec6dc12cd97b" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_770828fd-4653-459b-b6c9-034463f73429" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EarningsPerShareNarrativeTable_d10a305c-3e94-4d73-ab0e-2f672abf2a7c" xlink:href="frt-20211231.xsd#frt_EarningsPerShareNarrativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01195fd6-980b-4c7f-968f-ec6dc12cd97b" xlink:to="loc_frt_EarningsPerShareNarrativeTable_d10a305c-3e94-4d73-ab0e-2f672abf2a7c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_e33863b9-486f-435f-9e98-b537991f3941" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frt_EarningsPerShareNarrativeTable_d10a305c-3e94-4d73-ab0e-2f672abf2a7c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_e33863b9-486f-435f-9e98-b537991f3941" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e33863b9-486f-435f-9e98-b537991f3941_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e33863b9-486f-435f-9e98-b537991f3941" xlink:to="loc_us-gaap_ClassOfStockDomain_e33863b9-486f-435f-9e98-b537991f3941_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_3e5fde81-494d-49f2-b64c-d28bf3064256" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e33863b9-486f-435f-9e98-b537991f3941" xlink:to="loc_us-gaap_ClassOfStockDomain_3e5fde81-494d-49f2-b64c-d28bf3064256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_095ff3e0-4953-4ecf-b08e-79a348f063e8" xlink:href="frt-20211231.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3e5fde81-494d-49f2-b64c-d28bf3064256" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_095ff3e0-4953-4ecf-b08e-79a348f063e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeAxis_e5de1c36-fb94-4a82-8c99-a13e55d972b7" xlink:href="frt-20211231.xsd#frt_ShareTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frt_EarningsPerShareNarrativeTable_d10a305c-3e94-4d73-ab0e-2f672abf2a7c" xlink:to="loc_frt_ShareTypeAxis_e5de1c36-fb94-4a82-8c99-a13e55d972b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeDomain_e5de1c36-fb94-4a82-8c99-a13e55d972b7_default" xlink:href="frt-20211231.xsd#frt_ShareTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ShareTypeAxis_e5de1c36-fb94-4a82-8c99-a13e55d972b7" xlink:to="loc_frt_ShareTypeDomain_e5de1c36-fb94-4a82-8c99-a13e55d972b7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeDomain_fc7a4763-76ae-4e00-b72b-5678e7ed1a31" xlink:href="frt-20211231.xsd#frt_ShareTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ShareTypeAxis_e5de1c36-fb94-4a82-8c99-a13e55d972b7" xlink:to="loc_frt_ShareTypeDomain_fc7a4763-76ae-4e00-b72b-5678e7ed1a31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockOptionsMember_f37cf1a5-2c64-4b42-ad00-8dd13cc858a0" xlink:href="frt-20211231.xsd#frt_StockOptionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ShareTypeDomain_fc7a4763-76ae-4e00-b72b-5678e7ed1a31" xlink:to="loc_frt_StockOptionsMember_f37cf1a5-2c64-4b42-ad00-8dd13cc858a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ForwardSalesContractsMember_c3223a39-bc9d-417e-b05f-efb983e2f168" xlink:href="frt-20211231.xsd#frt_ForwardSalesContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ShareTypeDomain_fc7a4763-76ae-4e00-b72b-5678e7ed1a31" xlink:to="loc_frt_ForwardSalesContractsMember_c3223a39-bc9d-417e-b05f-efb983e2f168" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PerformanceBasedUnvestedSharesMember_64d8fb63-750f-4842-869a-d7f8b0323fae" xlink:href="frt-20211231.xsd#frt_PerformanceBasedUnvestedSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ShareTypeDomain_fc7a4763-76ae-4e00-b72b-5678e7ed1a31" xlink:to="loc_frt_PerformanceBasedUnvestedSharesMember_64d8fb63-750f-4842-869a-d7f8b0323fae" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SubsequentEvent" xlink:type="simple" xlink:href="frt-20211231.xsd#SubsequentEvent"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SubsequentEvent" xlink:type="extended" id="ic30f86e433704f6f930e4353bbd05f51_SubsequentEvent">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_50c9ff73-5dc4-4faa-9368-37f875e081fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsTextBlock_16220580-c2c9-4a28-932e-b8cac271fbcc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventsTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_50c9ff73-5dc4-4faa-9368-37f875e081fa" xlink:to="loc_us-gaap_SubsequentEventsTextBlock_16220580-c2c9-4a28-932e-b8cac271fbcc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_31c84074-62ea-4480-ba5f-afc53339ebd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_50c9ff73-5dc4-4faa-9368-37f875e081fa" xlink:to="loc_us-gaap_SubsequentEventTable_31c84074-62ea-4480-ba5f-afc53339ebd8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_35681617-fb9e-4fc7-8fd2-6362164fd1e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_31c84074-62ea-4480-ba5f-afc53339ebd8" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_35681617-fb9e-4fc7-8fd2-6362164fd1e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_35681617-fb9e-4fc7-8fd2-6362164fd1e4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_35681617-fb9e-4fc7-8fd2-6362164fd1e4" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_35681617-fb9e-4fc7-8fd2-6362164fd1e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_26a38083-43cd-4404-ab3d-397b56582236" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_35681617-fb9e-4fc7-8fd2-6362164fd1e4" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_26a38083-43cd-4404-ab3d-397b56582236" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SubsequentEventDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#SubsequentEventDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SubsequentEventDetails" xlink:type="extended" id="i1c2e0e74faf24e978952a4234211289e_SubsequentEventDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_040682d3-69d3-40c6-a40c-210f066a6f2b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_103f52d0-69bb-4e64-bd18-c7881a4dd63d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_040682d3-69d3-40c6-a40c-210f066a6f2b" xlink:to="loc_us-gaap_SubsequentEventTable_103f52d0-69bb-4e64-bd18-c7881a4dd63d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_7eecdb2e-f2c6-434d-a2e6-00312653f6b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_103f52d0-69bb-4e64-bd18-c7881a4dd63d" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_7eecdb2e-f2c6-434d-a2e6-00312653f6b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_7eecdb2e-f2c6-434d-a2e6-00312653f6b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_7eecdb2e-f2c6-434d-a2e6-00312653f6b5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_7eecdb2e-f2c6-434d-a2e6-00312653f6b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_faa56fc8-28f8-4293-8399-4f960939fa7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_7eecdb2e-f2c6-434d-a2e6-00312653f6b5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_faa56fc8-28f8-4293-8399-4f960939fa7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_b850f0b2-5ce7-44d2-8c02-801919339a2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_faa56fc8-28f8-4293-8399-4f960939fa7b" xlink:to="loc_us-gaap_SubsequentEventMember_b850f0b2-5ce7-44d2-8c02-801919339a2c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ScheduleIIISummaryofRealEstateandAccumulatedDepreciationDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ScheduleIIISummaryofRealEstateandAccumulatedDepreciationDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ScheduleIIISummaryofRealEstateandAccumulatedDepreciationDetails" xlink:type="extended" id="i9bad2baaa9564f58bd180c5e50f005ab_ScheduleIIISummaryofRealEstateandAccumulatedDepreciationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_f1036634-8117-4cb6-a681-bb6e45459277" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_f1036634-8117-4cb6-a681-bb6e45459277" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_768dd381-41c3-4c1b-888a-33b179549384" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_768dd381-41c3-4c1b-888a-33b179549384" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_72303266-78f7-496d-a05a-b9dab252a844" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_72303266-78f7-496d-a05a-b9dab252a844" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts_bf45efdb-c88b-460c-9a07-41f39acdc0d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts_bf45efdb-c88b-460c-9a07-41f39acdc0d5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_e23693cc-17a7-46be-a4db-b5f33141ce0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_e23693cc-17a7-46be-a4db-b5f33141ce0b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_c6949f76-9ac7-4c43-82bd-c74fe745779a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_c6949f76-9ac7-4c43-82bd-c74fe745779a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateGrossAtCarryingValue_60327a8d-7508-4d2b-b49f-8df3486afaaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateGrossAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateGrossAtCarryingValue_60327a8d-7508-4d2b-b49f-8df3486afaaf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciation_7ed679bb-2561-4939-b5fd-8bc34e81ffba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAccumulatedDepreciation_7ed679bb-2561-4939-b5fd-8bc34e81ffba" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_40ba48a4-039b-4980-9f1d-b5a6053f7e0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_40ba48a4-039b-4980-9f1d-b5a6053f7e0a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_6436e048-c1e0-46d8-a1d8-95eac254fa29" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationByPropertyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_2e8774b3-9657-4828-b822-362e413ac61b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_6436e048-c1e0-46d8-a1d8-95eac254fa29" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_10dc08d1-3894-4b01-8dd8-dfcd61b03599" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_6436e048-c1e0-46d8-a1d8-95eac254fa29" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_10dc08d1-3894-4b01-8dd8-dfcd61b03599" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_10dc08d1-3894-4b01-8dd8-dfcd61b03599_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_10dc08d1-3894-4b01-8dd8-dfcd61b03599" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_10dc08d1-3894-4b01-8dd8-dfcd61b03599_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_10dc08d1-3894-4b01-8dd8-dfcd61b03599" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A29thPlaceMember_0b308225-06fd-4ae1-b242-747de237f7d4" xlink:href="frt-20211231.xsd#frt_A29thPlaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_A29thPlaceMember_0b308225-06fd-4ae1-b242-747de237f7d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AndorraShoppingCenterMember_1864a5f4-4fbd-474e-9639-43491a0500bb" xlink:href="frt-20211231.xsd#frt_AndorraShoppingCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_AndorraShoppingCenterMember_1864a5f4-4fbd-474e-9639-43491a0500bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AssemblySquareMarketPlaceAssemblyRowMember_9771a61f-a7c9-4068-b0ef-ca8f1ff9b3ab" xlink:href="frt-20211231.xsd#frt_AssemblySquareMarketPlaceAssemblyRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_AssemblySquareMarketPlaceAssemblyRowMember_9771a61f-a7c9-4068-b0ef-ca8f1ff9b3ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AzaleaMember_2c8fd668-4c36-4ec3-b642-326692a105a5" xlink:href="frt-20211231.xsd#frt_AzaleaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_AzaleaMember_2c8fd668-4c36-4ec3-b642-326692a105a5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BalaCynwydMember_626e6339-007b-426b-9610-4fa0c87ea37f" xlink:href="frt-20211231.xsd#frt_BalaCynwydMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BalaCynwydMember_626e6339-007b-426b-9610-4fa0c87ea37f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BarcroftPlazaMember_8d438f66-7585-4fab-b24b-a959576431d2" xlink:href="frt-20211231.xsd#frt_BarcroftPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BarcroftPlazaMember_8d438f66-7585-4fab-b24b-a959576431d2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BarracksRoadMember_d170a57a-d064-49cf-b73d-b90eece0ede5" xlink:href="frt-20211231.xsd#frt_BarracksRoadMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BarracksRoadMember_d170a57a-d064-49cf-b73d-b90eece0ede5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BellGardensMember_24a067fc-9c97-4d58-a550-fb33b70874a8" xlink:href="frt-20211231.xsd#frt_BellGardensMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BellGardensMember_24a067fc-9c97-4d58-a550-fb33b70874a8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BethesdaRowMember_017a902b-a167-4f26-9942-55044ab44ca3" xlink:href="frt-20211231.xsd#frt_BethesdaRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BethesdaRowMember_017a902b-a167-4f26-9942-55044ab44ca3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FallsPlazaMember_85b1f7ec-c4a3-4a29-8ff6-72d946deaf5d" xlink:href="frt-20211231.xsd#frt_FallsPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FallsPlazaMember_85b1f7ec-c4a3-4a29-8ff6-72d946deaf5d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BrickPlazaMember_85a1e2c6-d63d-47e0-9514-71fb6fe5ce3c" xlink:href="frt-20211231.xsd#frt_BrickPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BrickPlazaMember_85a1e2c6-d63d-47e0-9514-71fb6fe5ce3c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BristolMember_c17faac2-feb5-4c37-8dbb-6db78b29771f" xlink:href="frt-20211231.xsd#frt_BristolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_BristolMember_c17faac2-feb5-4c37-8dbb-6db78b29771f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Brook35Member_70f8cd5c-e503-43bc-9f79-7d036af2b52e" xlink:href="frt-20211231.xsd#frt_Brook35Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_Brook35Member_70f8cd5c-e503-43bc-9f79-7d036af2b52e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CamelbackColonnadeMember_45015435-0a47-455d-84c2-f66595e146a5" xlink:href="frt-20211231.xsd#frt_CamelbackColonnadeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CamelbackColonnadeMember_45015435-0a47-455d-84c2-f66595e146a5" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CampusPlazaMember_d855b720-ed5e-477e-a063-4e3c31945aa8" xlink:href="frt-20211231.xsd#frt_CampusPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CampusPlazaMember_d855b720-ed5e-477e-a063-4e3c31945aa8" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ChelseaMember_7b8df5c9-fda9-4ac8-9478-a38556f42ab6" xlink:href="frt-20211231.xsd#frt_ChelseaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ChelseaMember_7b8df5c9-fda9-4ac8-9478-a38556f42ab6" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ChesterbrookMember_6961564d-26d8-4563-b54b-284a1e85adfd" xlink:href="frt-20211231.xsd#frt_ChesterbrookMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ChesterbrookMember_6961564d-26d8-4563-b54b-284a1e85adfd" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CocoWalkMember_dcfa5cea-e5b1-4467-8b37-a95d45985e3d" xlink:href="frt-20211231.xsd#frt_CocoWalkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CocoWalkMember_dcfa5cea-e5b1-4467-8b37-a95d45985e3d" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ColoradoBlvdMember_73a06286-4039-44f1-9fac-e39952cf3080" xlink:href="frt-20211231.xsd#frt_ColoradoBlvdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ColoradoBlvdMember_73a06286-4039-44f1-9fac-e39952cf3080" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CongressionalPlazaMember_fb85cc39-d722-4e02-b398-40a313c4ab3a" xlink:href="frt-20211231.xsd#frt_CongressionalPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CongressionalPlazaMember_fb85cc39-d722-4e02-b398-40a313c4ab3a" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CourthouseCenterMember_3c51e8c3-1d53-43dc-988b-bb577febb935" xlink:href="frt-20211231.xsd#frt_CourthouseCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CourthouseCenterMember_3c51e8c3-1d53-43dc-988b-bb577febb935" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CrossroadsMember_05f8b2ff-6dbe-420e-ac16-49af4de5d8f0" xlink:href="frt-20211231.xsd#frt_CrossroadsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CrossroadsMember_05f8b2ff-6dbe-420e-ac16-49af4de5d8f0" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CrowCanyonMember_e8f1e8a6-b8d5-4801-b301-82d5e4ebcc32" xlink:href="frt-20211231.xsd#frt_CrowCanyonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_CrowCanyonMember_e8f1e8a6-b8d5-4801-b301-82d5e4ebcc32" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DarienMember_8fb8ac2d-710a-4849-b81b-adcadc88b4a1" xlink:href="frt-20211231.xsd#frt_DarienMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_DarienMember_8fb8ac2d-710a-4849-b81b-adcadc88b4a1" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DedhamPlazaMember_32048de4-d0e3-4678-b9e1-5a3f7ae42d62" xlink:href="frt-20211231.xsd#frt_DedhamPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_DedhamPlazaMember_32048de4-d0e3-4678-b9e1-5a3f7ae42d62" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DelMarVillageMember_8fc0cb87-2b15-45f1-b9e7-ddab5f43dec7" xlink:href="frt-20211231.xsd#frt_DelMarVillageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_DelMarVillageMember_8fc0cb87-2b15-45f1-b9e7-ddab5f43dec7" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EastBayBridgeMember_96bd3cf4-1218-47f5-9990-8739bbe01bd3" xlink:href="frt-20211231.xsd#frt_EastBayBridgeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_EastBayBridgeMember_96bd3cf4-1218-47f5-9990-8739bbe01bd3" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ElllisburgCircleMember_cd929b6b-3a5a-4021-8824-16b325e1cc3c" xlink:href="frt-20211231.xsd#frt_ElllisburgCircleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ElllisburgCircleMember_cd929b6b-3a5a-4021-8824-16b325e1cc3c" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EscondidoPromenadeMember_e97b37a6-cc4c-42b6-b168-26011728a963" xlink:href="frt-20211231.xsd#frt_EscondidoPromenadeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_EscondidoPromenadeMember_e97b37a6-cc4c-42b6-b168-26011728a963" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FairfaxJunctionMember_4fcc3a3b-0933-4a04-babf-67546d0b0783" xlink:href="frt-20211231.xsd#frt_FairfaxJunctionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FairfaxJunctionMember_4fcc3a3b-0933-4a04-babf-67546d0b0783" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FederalPlazaMember_42593df6-aab7-4f6d-9d6d-4d0195bec317" xlink:href="frt-20211231.xsd#frt_FederalPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FederalPlazaMember_42593df6-aab7-4f6d-9d6d-4d0195bec317" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FinleySquareMember_a2f3e4b0-c038-42f5-9bb4-abc38ec458f1" xlink:href="frt-20211231.xsd#frt_FinleySquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FinleySquareMember_a2f3e4b0-c038-42f5-9bb4-abc38ec458f1" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FlourtownMember_56994a27-695d-48db-9e49-28cdddbafbb9" xlink:href="frt-20211231.xsd#frt_FlourtownMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FlourtownMember_56994a27-695d-48db-9e49-28cdddbafbb9" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FourthStreetMember_6c5f0d43-498d-4ae0-ba0b-9c7ea4ae9796" xlink:href="frt-20211231.xsd#frt_FourthStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FourthStreetMember_6c5f0d43-498d-4ae0-ba0b-9c7ea4ae9796" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_JordanDownsPlazaMember_02d54085-142c-41e3-9cc8-402c15fb8b56" xlink:href="frt-20211231.xsd#frt_JordanDownsPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_JordanDownsPlazaMember_02d54085-142c-41e3-9cc8-402c15fb8b56" xlink:type="arc" order="34"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FreshMeadowsMember_937c049c-c516-4977-a636-2ae899a6e5f1" xlink:href="frt-20211231.xsd#frt_FreshMeadowsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FreshMeadowsMember_937c049c-c516-4977-a636-2ae899a6e5f1" xlink:type="arc" order="35"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FriendshipCtrMember_a63d2884-389e-45ca-a981-f332bf05dcd5" xlink:href="frt-20211231.xsd#frt_FriendshipCtrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_FriendshipCtrMember_a63d2884-389e-45ca-a981-f332bf05dcd5" xlink:type="arc" order="36"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GaithersburgSquareMember_1bc80284-7db3-470f-9314-b5ab4b893721" xlink:href="frt-20211231.xsd#frt_GaithersburgSquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GaithersburgSquareMember_1bc80284-7db3-470f-9314-b5ab4b893721" xlink:type="arc" order="37"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GardenMarketMember_08b3ebd8-ffc7-4b8d-a44c-3da351f58c8c" xlink:href="frt-20211231.xsd#frt_GardenMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GardenMarketMember_08b3ebd8-ffc7-4b8d-a44c-3da351f58c8c" xlink:type="arc" order="38"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GeorgetowneShoppingCenterMember_f43a790b-7b99-406a-a80d-504ab92fe619" xlink:href="frt-20211231.xsd#frt_GeorgetowneShoppingCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GeorgetowneShoppingCenterMember_f43a790b-7b99-406a-a80d-504ab92fe619" xlink:type="arc" order="39"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GovernorPlazaMember_3201fe25-0098-4291-9448-63f18b6cce00" xlink:href="frt-20211231.xsd#frt_GovernorPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GovernorPlazaMember_3201fe25-0098-4291-9448-63f18b6cce00" xlink:type="arc" order="40"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrahamParkMember_9b4cfa45-8ed0-434a-a8b3-10d8d72f937b" xlink:href="frt-20211231.xsd#frt_GrahamParkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GrahamParkMember_9b4cfa45-8ed0-434a-a8b3-10d8d72f937b" xlink:type="arc" order="41"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GratiotPlazaMember_cfd1b4d1-2439-4a0c-ab71-ba81ab87a5d1" xlink:href="frt-20211231.xsd#frt_GratiotPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GratiotPlazaMember_cfd1b4d1-2439-4a0c-ab71-ba81ab87a5d1" xlink:type="arc" order="42"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GreenlawnPlazaMember_574c4baf-3769-4a8f-bd79-384b7ad6a665" xlink:href="frt-20211231.xsd#frt_GreenlawnPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GreenlawnPlazaMember_574c4baf-3769-4a8f-bd79-384b7ad6a665" xlink:type="arc" order="43"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GreenwichAvenueMember_e5b74a71-40ee-4038-b9e2-0d2b0ee90681" xlink:href="frt-20211231.xsd#frt_GreenwichAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GreenwichAvenueMember_e5b74a71-40ee-4038-b9e2-0d2b0ee90681" xlink:type="arc" order="44"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GrossmontCenterMember_f346a14b-5297-4504-8f3e-60d583bcdb38" xlink:href="frt-20211231.xsd#frt_GrossmontCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_GrossmontCenterMember_f346a14b-5297-4504-8f3e-60d583bcdb38" xlink:type="arc" order="45"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HastingsRanchPlazaMember_94e4ad12-4bee-47e0-ab83-8e9572d1cdc0" xlink:href="frt-20211231.xsd#frt_HastingsRanchPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HastingsRanchPlazaMember_94e4ad12-4bee-47e0-ab83-8e9572d1cdc0" xlink:type="arc" order="46"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HauppaugeMember_88a88bdf-fc9e-4fed-a93a-3854b93a56b0" xlink:href="frt-20211231.xsd#frt_HauppaugeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HauppaugeMember_88a88bdf-fc9e-4fed-a93a-3854b93a56b0" xlink:type="arc" order="47"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HiltonVillageMember_6b8a277e-4132-45d1-b443-acbc5429c36d" xlink:href="frt-20211231.xsd#frt_HiltonVillageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HiltonVillageMember_6b8a277e-4132-45d1-b443-acbc5429c36d" xlink:type="arc" order="48"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_0d78392f-25aa-4607-bf10-34d2ee6c917d" xlink:href="frt-20211231.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HobokenMember_0d78392f-25aa-4607-bf10-34d2ee6c917d" xlink:type="arc" order="49"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HollywoodBlvdMember_dd9d9577-c1a8-47fe-92b7-8e286c644c92" xlink:href="frt-20211231.xsd#frt_HollywoodBlvdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HollywoodBlvdMember_dd9d9577-c1a8-47fe-92b7-8e286c644c92" xlink:type="arc" order="50"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HuntingtonMember_9badc42b-9b6e-45b2-94a2-cc5e468edd2c" xlink:href="frt-20211231.xsd#frt_HuntingtonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HuntingtonMember_9badc42b-9b6e-45b2-94a2-cc5e468edd2c" xlink:type="arc" order="51"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HuntingtonsquareMember_af83c232-1906-4c3f-acb9-ae205f28946a" xlink:href="frt-20211231.xsd#frt_HuntingtonsquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_HuntingtonsquareMember_af83c232-1906-4c3f-acb9-ae205f28946a" xlink:type="arc" order="52"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_IdylwoodPlazaMember_d7878ff4-2f35-4a5d-a105-eb68bcf6e368" xlink:href="frt-20211231.xsd#frt_IdylwoodPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_IdylwoodPlazaMember_d7878ff4-2f35-4a5d-a105-eb68bcf6e368" xlink:type="arc" order="53"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_KingsCourtMember_90aa17d5-e427-4974-8f37-3dd7fcbe557f" xlink:href="frt-20211231.xsd#frt_KingsCourtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_KingsCourtMember_90aa17d5-e427-4974-8f37-3dd7fcbe557f" xlink:type="arc" order="54"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LancasterMember_04e53306-58db-4980-86c4-581a33995b4e" xlink:href="frt-20211231.xsd#frt_LancasterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_LancasterMember_04e53306-58db-4980-86c4-581a33995b4e" xlink:type="arc" order="55"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LanghorneSquareMember_926aea3f-476c-4dbe-92e7-29f30a33aca2" xlink:href="frt-20211231.xsd#frt_LanghorneSquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_LanghorneSquareMember_926aea3f-476c-4dbe-92e7-29f30a33aca2" xlink:type="arc" order="56"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LaurelMember_3ffef4d7-ac41-4cd9-a7af-f88b1c00eab0" xlink:href="frt-20211231.xsd#frt_LaurelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_LaurelMember_3ffef4d7-ac41-4cd9-a7af-f88b1c00eab0" xlink:type="arc" order="57"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LawrenceParkMember_09b6ccb3-2e7a-43c0-945f-6bd26a098a8c" xlink:href="frt-20211231.xsd#frt_LawrenceParkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_LawrenceParkMember_09b6ccb3-2e7a-43c0-945f-6bd26a098a8c" xlink:type="arc" order="58"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LindenSquareMember_a354cb7f-b9f8-4235-be9d-3fde86b3719e" xlink:href="frt-20211231.xsd#frt_LindenSquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_LindenSquareMember_a354cb7f-b9f8-4235-be9d-3fde86b3719e" xlink:type="arc" order="59"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MelvilleMallMember_ad97c27d-5b19-4297-824d-a150d6a69888" xlink:href="frt-20211231.xsd#frt_MelvilleMallMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_MelvilleMallMember_ad97c27d-5b19-4297-824d-a150d6a69888" xlink:type="arc" order="60"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MercerMallMember_6f0cec4e-e332-4382-8a9e-b87f603631b9" xlink:href="frt-20211231.xsd#frt_MercerMallMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_MercerMallMember_6f0cec4e-e332-4382-8a9e-b87f603631b9" xlink:type="arc" order="61"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MontroseCrossingMember_5c581887-32df-43e2-b828-39f67b571351" xlink:href="frt-20211231.xsd#frt_MontroseCrossingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_MontroseCrossingMember_5c581887-32df-43e2-b828-39f67b571351" xlink:type="arc" order="62"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MountVernonMember_ec269ebd-e1da-455a-9b72-f2b6506d397e" xlink:href="frt-20211231.xsd#frt_MountVernonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_MountVernonMember_ec269ebd-e1da-455a-9b72-f2b6506d397e" xlink:type="arc" order="63"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NorthDartmouthMember_86c05ac5-e16a-4a56-a982-fba9165b7100" xlink:href="frt-20211231.xsd#frt_NorthDartmouthMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_NorthDartmouthMember_86c05ac5-e16a-4a56-a982-fba9165b7100" xlink:type="arc" order="64"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NortheastMember_f9c41cf2-4a46-437a-a309-48e7bf878e0e" xlink:href="frt-20211231.xsd#frt_NortheastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_NortheastMember_f9c41cf2-4a46-437a-a309-48e7bf878e0e" xlink:type="arc" order="65"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OldKeeneMillMember_a34420cf-48ad-40d8-835d-b40fa2360bad" xlink:href="frt-20211231.xsd#frt_OldKeeneMillMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_OldKeeneMillMember_a34420cf-48ad-40d8-835d-b40fa2360bad" xlink:type="arc" order="66"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OldTownCenterMember_2440c58c-9368-4dd4-bfb6-de52942131cc" xlink:href="frt-20211231.xsd#frt_OldTownCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_OldTownCenterMember_2440c58c-9368-4dd4-bfb6-de52942131cc" xlink:type="arc" order="67"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OlivoatMissionHillsMember_7baf8069-ec2a-42cd-b512-52e872b9303d" xlink:href="frt-20211231.xsd#frt_OlivoatMissionHillsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_OlivoatMissionHillsMember_7baf8069-ec2a-42cd-b512-52e872b9303d" xlink:type="arc" order="68"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PanAmShoppingCenterMember_93fc2eec-125b-4827-96b2-27f205d043d1" xlink:href="frt-20211231.xsd#frt_PanAmShoppingCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PanAmShoppingCenterMember_93fc2eec-125b-4827-96b2-27f205d043d1" xlink:type="arc" order="69"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PentagonRowMember_823b7211-fc68-43b8-9ef0-57965fcb49dd" xlink:href="frt-20211231.xsd#frt_PentagonRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PentagonRowMember_823b7211-fc68-43b8-9ef0-57965fcb49dd" xlink:type="arc" order="70"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PerringPlazaMember_07dfaae1-e971-4e25-b92f-cd142648b146" xlink:href="frt-20211231.xsd#frt_PerringPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PerringPlazaMember_07dfaae1-e971-4e25-b92f-cd142648b146" xlink:type="arc" order="71"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PikeRoseMember_d9c64203-1112-49f7-8f2b-b6c60a38f7be" xlink:href="frt-20211231.xsd#frt_PikeRoseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PikeRoseMember_d9c64203-1112-49f7-8f2b-b6c60a38f7be" xlink:type="arc" order="72"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Pike7Member_8a5d0238-0294-4fc7-a428-706fc0e97cb2" xlink:href="frt-20211231.xsd#frt_Pike7Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_Pike7Member_8a5d0238-0294-4fc7-a428-706fc0e97cb2" xlink:type="arc" order="73"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaDelMercadoMember_5f583617-ca5c-4b5d-a32a-51ebe7c1b1af" xlink:href="frt-20211231.xsd#frt_PlazaDelMercadoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PlazaDelMercadoMember_5f583617-ca5c-4b5d-a32a-51ebe7c1b1af" xlink:type="arc" order="74"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaDelSolMember_9f8da0b3-d6dc-45f0-bf5a-ba274c579bf4" xlink:href="frt-20211231.xsd#frt_PlazaDelSolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PlazaDelSolMember_9f8da0b3-d6dc-45f0-bf5a-ba274c579bf4" xlink:type="arc" order="75"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PlazaElSegundoThePointMember_9d71cb60-7074-41dd-a773-f836de81facf" xlink:href="frt-20211231.xsd#frt_PlazaElSegundoThePointMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_PlazaElSegundoThePointMember_9d71cb60-7074-41dd-a773-f836de81facf" xlink:type="arc" order="76"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_QueenAnnePlazaMember_1c2ec92f-9270-44c3-b212-b1ffcd9a6612" xlink:href="frt-20211231.xsd#frt_QueenAnnePlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_QueenAnnePlazaMember_1c2ec92f-9270-44c3-b212-b1ffcd9a6612" xlink:type="arc" order="77"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_QuinceOrchardPlazaMember_63b71fd9-8fbc-4f60-b307-e94d5f6113bb" xlink:href="frt-20211231.xsd#frt_QuinceOrchardPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_QuinceOrchardPlazaMember_63b71fd9-8fbc-4f60-b307-e94d5f6113bb" xlink:type="arc" order="78"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RiverpointCenterMember_add431d4-5639-4a1d-bf3d-d9a4eff6ae16" xlink:href="frt-20211231.xsd#frt_RiverpointCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_RiverpointCenterMember_add431d4-5639-4a1d-bf3d-d9a4eff6ae16" xlink:type="arc" order="79"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RockvilleTownSquareMember_72c9ff64-e8d6-449b-bd48-fea7b694d02d" xlink:href="frt-20211231.xsd#frt_RockvilleTownSquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_RockvilleTownSquareMember_72c9ff64-e8d6-449b-bd48-fea7b694d02d" xlink:type="arc" order="80"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RollingwoodApartmentsMember_023725db-1da0-4f4f-aaea-a35ff79cce9d" xlink:href="frt-20211231.xsd#frt_RollingwoodApartmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_RollingwoodApartmentsMember_023725db-1da0-4f4f-aaea-a35ff79cce9d" xlink:type="arc" order="81"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SanAntonioCenterMember_3ed47d47-5459-4b3c-adf5-5abbfe542792" xlink:href="frt-20211231.xsd#frt_SanAntonioCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_SanAntonioCenterMember_3ed47d47-5459-4b3c-adf5-5abbfe542792" xlink:type="arc" order="82"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SantanaRowMember_23acf7a8-35d9-40c3-809c-9a64c98d3329" xlink:href="frt-20211231.xsd#frt_SantanaRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_SantanaRowMember_23acf7a8-35d9-40c3-809c-9a64c98d3329" xlink:type="arc" order="83"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SylmarTowneCenterMember_2b1d89c8-ff42-419c-8145-e559fba47589" xlink:href="frt-20211231.xsd#frt_SylmarTowneCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_SylmarTowneCenterMember_2b1d89c8-ff42-419c-8145-e559fba47589" xlink:type="arc" order="84"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AvenueAtWhiteMarshMember_db54881b-7238-46d6-93ed-08c8becf9aa2" xlink:href="frt-20211231.xsd#frt_AvenueAtWhiteMarshMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_AvenueAtWhiteMarshMember_db54881b-7238-46d6-93ed-08c8becf9aa2" xlink:type="arc" order="85"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TheGroveatShrewsburyMember_04d8c410-f199-4670-81d8-485cb4056219" xlink:href="frt-20211231.xsd#frt_TheGroveatShrewsburyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TheGroveatShrewsburyMember_04d8c410-f199-4670-81d8-485cb4056219" xlink:type="arc" order="86"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShoppesAtNottinghamSquareMember_9519a977-d4ea-4ad6-933b-f1e351541201" xlink:href="frt-20211231.xsd#frt_ShoppesAtNottinghamSquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ShoppesAtNottinghamSquareMember_9519a977-d4ea-4ad6-933b-f1e351541201" xlink:type="arc" order="87"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ThirdStreetPromenadeMember_dab2e600-0172-4d77-aa72-056f4aedc794" xlink:href="frt-20211231.xsd#frt_ThirdStreetPromenadeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ThirdStreetPromenadeMember_dab2e600-0172-4d77-aa72-056f4aedc794" xlink:type="arc" order="88"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TowerMember_7647195e-8979-453e-a2a5-39caf91c9731" xlink:href="frt-20211231.xsd#frt_TowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TowerMember_7647195e-8979-453e-a2a5-39caf91c9731" xlink:type="arc" order="89"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TowerShopsJanuary192011Member_5ab5a89f-fd20-49e2-905e-a6b9a220cfbf" xlink:href="frt-20211231.xsd#frt_TowerShopsJanuary192011Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TowerShopsJanuary192011Member_5ab5a89f-fd20-49e2-905e-a6b9a220cfbf" xlink:type="arc" order="90"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TownCenterOfNewBritainMember_ca5e2b34-e6ab-4932-9067-e90a4063ea3a" xlink:href="frt-20211231.xsd#frt_TownCenterOfNewBritainMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TownCenterOfNewBritainMember_ca5e2b34-e6ab-4932-9067-e90a4063ea3a" xlink:type="arc" order="91"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TownsonResidentialMember_9a8d66d2-097b-4078-bb20-f404b20e69ea" xlink:href="frt-20211231.xsd#frt_TownsonResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TownsonResidentialMember_9a8d66d2-097b-4078-bb20-f404b20e69ea" xlink:type="arc" order="92"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TroyMember_6f4369aa-556b-4800-9e17-5fb7bc6cd636" xlink:href="frt-20211231.xsd#frt_TroyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TroyMember_6f4369aa-556b-4800-9e17-5fb7bc6cd636" xlink:type="arc" order="93"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TwinbrookeShoppingCentreMember_e5430eef-5176-4f57-b895-3deeb7677c52" xlink:href="frt-20211231.xsd#frt_TwinbrookeShoppingCentreMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TwinbrookeShoppingCentreMember_e5430eef-5176-4f57-b895-3deeb7677c52" xlink:type="arc" order="94"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TysonStationMember_3e1131ab-2746-4c38-8f7a-8091d840ecf7" xlink:href="frt-20211231.xsd#frt_TysonStationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_TysonStationMember_3e1131ab-2746-4c38-8f7a-8091d840ecf7" xlink:type="arc" order="95"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShirlingtonMember_148ccaf0-8f43-4df5-a84f-35b7f7ed8e7a" xlink:href="frt-20211231.xsd#frt_ShirlingtonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_ShirlingtonMember_148ccaf0-8f43-4df5-a84f-35b7f7ed8e7a" xlink:type="arc" order="96"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WestgateMallMember_d8979c6e-8fd5-4c3a-91d5-26e351c9ee43" xlink:href="frt-20211231.xsd#frt_WestgateMallMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WestgateMallMember_d8979c6e-8fd5-4c3a-91d5-26e351c9ee43" xlink:type="arc" order="97"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WhiteMarshPlazaMember_e0590ba8-9bb5-4bd6-9740-90015614b184" xlink:href="frt-20211231.xsd#frt_WhiteMarshPlazaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WhiteMarshPlazaMember_e0590ba8-9bb5-4bd6-9740-90015614b184" xlink:type="arc" order="98"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WhiteMarshOtherMember_ef7630b4-1895-4619-8e4d-0c0175383b1f" xlink:href="frt-20211231.xsd#frt_WhiteMarshOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WhiteMarshOtherMember_ef7630b4-1895-4619-8e4d-0c0175383b1f" xlink:type="arc" order="99"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WildwoodMember_37d49e87-60a3-477d-8d50-6e989706c7dc" xlink:href="frt-20211231.xsd#frt_WildwoodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WildwoodMember_37d49e87-60a3-477d-8d50-6e989706c7dc" xlink:type="arc" order="100"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WillowGroveMember_b5574ae4-7d7c-4caf-aa3a-5dc28384c8cb" xlink:href="frt-20211231.xsd#frt_WillowGroveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WillowGroveMember_b5574ae4-7d7c-4caf-aa3a-5dc28384c8cb" xlink:type="arc" order="101"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WillowLawnMember_dc2f4866-810e-4964-9750-78997e86a9d4" xlink:href="frt-20211231.xsd#frt_WillowLawnMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WillowLawnMember_dc2f4866-810e-4964-9750-78997e86a9d4" xlink:type="arc" order="102"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WynnewoodMember_80dc5449-69bb-4718-be9b-e1c3261c7857" xlink:href="frt-20211231.xsd#frt_WynnewoodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_3fa2cecd-c94d-429c-a675-5f6a73bea166" xlink:to="loc_frt_WynnewoodMember_80dc5449-69bb-4718-be9b-e1c3261c7857" xlink:type="arc" order="103"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_41895cce-7242-4bd9-80e9-2a0ab143128b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_6436e048-c1e0-46d8-a1d8-95eac254fa29" xlink:to="loc_srt_RangeAxis_41895cce-7242-4bd9-80e9-2a0ab143128b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_41895cce-7242-4bd9-80e9-2a0ab143128b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_41895cce-7242-4bd9-80e9-2a0ab143128b" xlink:to="loc_srt_RangeMember_41895cce-7242-4bd9-80e9-2a0ab143128b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_be5175b6-a152-4bcb-b8d2-d67280b196b0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_41895cce-7242-4bd9-80e9-2a0ab143128b" xlink:to="loc_srt_RangeMember_be5175b6-a152-4bcb-b8d2-d67280b196b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_41499fd9-b37f-4a23-8e83-e7ce77b05bd1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_be5175b6-a152-4bcb-b8d2-d67280b196b0" xlink:to="loc_srt_MaximumMember_41499fd9-b37f-4a23-8e83-e7ce77b05bd1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ScheduleIIIPartIISummaryofRealEstateandAccumulatedDepreciationDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ScheduleIIIPartIISummaryofRealEstateandAccumulatedDepreciationDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ScheduleIIIPartIISummaryofRealEstateandAccumulatedDepreciationDetails" xlink:type="extended" id="ib3d5b98114c147858d7bc6d88928a407_ScheduleIIIPartIISummaryofRealEstateandAccumulatedDepreciationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4d9b1df4-8633-4a78-be00-fd41dc44cb65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ReductionofRealEstate_4cdeef78-1330-4d6b-8a83-a121a7a96d06" xlink:href="frt-20211231.xsd#frt_ReductionofRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d9b1df4-8633-4a78-be00-fd41dc44cb65" xlink:to="loc_frt_ReductionofRealEstate_4cdeef78-1330-4d6b-8a83-a121a7a96d06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ReductionofAccumulatedDepreciationandAmortizationofRealEstate_a88a91fd-0f29-4e68-b208-57d37acb01bb" xlink:href="frt-20211231.xsd#frt_ReductionofAccumulatedDepreciationandAmortizationofRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d9b1df4-8633-4a78-be00-fd41dc44cb65" xlink:to="loc_frt_ReductionofAccumulatedDepreciationandAmortizationofRealEstate_a88a91fd-0f29-4e68-b208-57d37acb01bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_8c15cbd3-4c06-4d07-92d3-56347e114ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4d9b1df4-8633-4a78-be00-fd41dc44cb65" xlink:to="loc_us-gaap_StatementTable_8c15cbd3-4c06-4d07-92d3-56347e114ac7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_a55ea9fd-9a77-4c86-82bc-ca5401b34713" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_8c15cbd3-4c06-4d07-92d3-56347e114ac7" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_a55ea9fd-9a77-4c86-82bc-ca5401b34713" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_a55ea9fd-9a77-4c86-82bc-ca5401b34713_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_a55ea9fd-9a77-4c86-82bc-ca5401b34713" xlink:to="loc_us-gaap_TypeOfAdoptionMember_a55ea9fd-9a77-4c86-82bc-ca5401b34713_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_48ef747b-6d51-49c2-8236-cba7bd91fb05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_a55ea9fd-9a77-4c86-82bc-ca5401b34713" xlink:to="loc_us-gaap_TypeOfAdoptionMember_48ef747b-6d51-49c2-8236-cba7bd91fb05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_33f1acf0-5e84-4445-90a2-1d7dfb9e2fe9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_48ef747b-6d51-49c2-8236-cba7bd91fb05" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_33f1acf0-5e84-4445-90a2-1d7dfb9e2fe9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ScheduleIVMortgageLoansonRealEstateDetails" xlink:type="simple" xlink:href="frt-20211231.xsd#ScheduleIVMortgageLoansonRealEstateDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ScheduleIVMortgageLoansonRealEstateDetails" xlink:type="extended" id="ic708973d78f84821addd8aacb0904878_ScheduleIVMortgageLoansonRealEstateDetails">
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgageLoansOnRealEstateParticipationPlusInterestRateInterestRate_47fda5e0-40b7-49e6-bd1c-8c8e8e261885" xlink:href="frt-20211231.xsd#frt_MortgageLoansOnRealEstateParticipationPlusInterestRateInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_frt_MortgageLoansOnRealEstateParticipationPlusInterestRateInterestRate_47fda5e0-40b7-49e6-bd1c-8c8e8e261885" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstatePriorLiens1_4e075333-35f2-4f22-8f6c-c54b56195d6a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstatePriorLiens1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_srt_MortgageLoansOnRealEstatePriorLiens1_4e075333-35f2-4f22-8f6c-c54b56195d6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateFaceAmountOfMortgages_91600334-a928-4a0d-8e33-be90d4edcf3a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateFaceAmountOfMortgages"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_srt_MortgageLoansOnRealEstateFaceAmountOfMortgages_91600334-a928-4a0d-8e33-be90d4edcf3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstate_915e8f2e-3645-4b66-a272-156c6792f24e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_us-gaap_MortgageLoansOnRealEstate_915e8f2e-3645-4b66-a272-156c6792f24e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans_c38c0a50-e292-4cdc-b747-a254a200fe1f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_srt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans_c38c0a50-e292-4cdc-b747-a254a200fe1f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateOtherRequiredDisclosuresAbstract_399feb9e-a4a2-4e69-92fe-c2656c125c3c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateOtherRequiredDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_srt_MortgageLoansOnRealEstateOtherRequiredDisclosuresAbstract_399feb9e-a4a2-4e69-92fe-c2656c125c3c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateFederalIncomeTaxBasis1_1c8d3c52-1382-4aeb-af9b-3a7d48c953a8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateFederalIncomeTaxBasis1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateOtherRequiredDisclosuresAbstract_399feb9e-a4a2-4e69-92fe-c2656c125c3c" xlink:to="loc_srt_MortgageLoansOnRealEstateFederalIncomeTaxBasis1_1c8d3c52-1382-4aeb-af9b-3a7d48c953a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MovementInMortgageLoansOnRealEstateRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstate_0f397f04-b6c7-4ffd-acaa-bc42573db220" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstate"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_January12020AdoptionOfNewAccountingStandard_7aa26ffe-f726-4742-8a76-138386f317b5" xlink:href="frt-20211231.xsd#frt_January12020AdoptionOfNewAccountingStandard"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:to="loc_frt_January12020AdoptionOfNewAccountingStandard_7aa26ffe-f726-4742-8a76-138386f317b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AcquisitionsOfLoansNetOfValuationAdjustements_3c720602-d358-4a08-bdf6-10ed95b31e0b" xlink:href="frt-20211231.xsd#frt_AcquisitionsOfLoansNetOfValuationAdjustements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:to="loc_frt_AcquisitionsOfLoansNetOfValuationAdjustements_3c720602-d358-4a08-bdf6-10ed95b31e0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstateNewMortgageLoans_854563f4-b834-4572-bd4b-7293ca35464c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstateNewMortgageLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:to="loc_us-gaap_MortgageLoansOnRealEstateNewMortgageLoans_854563f4-b834-4572-bd4b-7293ca35464c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateCollectionsOfPrincipal_7c40f20e-ef77-4f8f-8c89-943703b75278" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateCollectionsOfPrincipal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:to="loc_srt_MortgageLoansOnRealEstateCollectionsOfPrincipal_7c40f20e-ef77-4f8f-8c89-943703b75278" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ValuationAdjustments_1b33f19c-b628-42e8-97bd-9aab53a50cab" xlink:href="frt-20211231.xsd#frt_ValuationAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMortgageLoansOnRealEstateRollForward_bb40effd-afc2-4d91-ab20-fe5c266d2831" xlink:to="loc_frt_ValuationAdjustments_1b33f19c-b628-42e8-97bd-9aab53a50cab" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstate_900b3b99-b4e5-4797-895f-7eb4a5a10a24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstate"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateScheduleTable_b287498c-5eeb-4f0c-8e3e-61d5c9b6bd78" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateScheduleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_MortgageLoansOnRealEstateLineItems_be978f6a-8f0b-49b6-989c-bd2466291cc1" xlink:to="loc_srt_MortgageLoansOnRealEstateScheduleTable_b287498c-5eeb-4f0c-8e3e-61d5c9b6bd78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_InterestRateAxis_189ae969-8210-49be-9aa2-6c73813cbf5f" xlink:href="frt-20211231.xsd#frt_InterestRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_MortgageLoansOnRealEstateScheduleTable_b287498c-5eeb-4f0c-8e3e-61d5c9b6bd78" xlink:to="loc_frt_InterestRateAxis_189ae969-8210-49be-9aa2-6c73813cbf5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_InterestRateDomain_189ae969-8210-49be-9aa2-6c73813cbf5f_default" xlink:href="frt-20211231.xsd#frt_InterestRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_InterestRateAxis_189ae969-8210-49be-9aa2-6c73813cbf5f" xlink:to="loc_frt_InterestRateDomain_189ae969-8210-49be-9aa2-6c73813cbf5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_InterestRateDomain_c2a17dff-aa00-41fe-b72d-c5626ccc7240" xlink:href="frt-20211231.xsd#frt_InterestRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_InterestRateAxis_189ae969-8210-49be-9aa2-6c73813cbf5f" xlink:to="loc_frt_InterestRateDomain_c2a17dff-aa00-41fe-b72d-c5626ccc7240" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_InterestRateOneMember_179e9ef3-d55c-4e78-b8ea-8b2d634961eb" xlink:href="frt-20211231.xsd#frt_InterestRateOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_InterestRateDomain_c2a17dff-aa00-41fe-b72d-c5626ccc7240" xlink:to="loc_frt_InterestRateOneMember_179e9ef3-d55c-4e78-b8ea-8b2d634961eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_InterestRateTwoMember_9c9438a6-784e-492a-acc8-fd790c22e256" xlink:href="frt-20211231.xsd#frt_InterestRateTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_InterestRateDomain_c2a17dff-aa00-41fe-b72d-c5626ccc7240" xlink:to="loc_frt_InterestRateTwoMember_9c9438a6-784e-492a-acc8-fd790c22e256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_e783d94d-169a-4b32-9f32-e24b10452fa8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_MortgageLoansOnRealEstateScheduleTable_b287498c-5eeb-4f0c-8e3e-61d5c9b6bd78" xlink:to="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_e783d94d-169a-4b32-9f32-e24b10452fa8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_e783d94d-169a-4b32-9f32-e24b10452fa8_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_e783d94d-169a-4b32-9f32-e24b10452fa8" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_e783d94d-169a-4b32-9f32-e24b10452fa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_4141085a-4f8c-4556-8ad4-723464d6b3f4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_e783d94d-169a-4b32-9f32-e24b10452fa8" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_4141085a-4f8c-4556-8ad4-723464d6b3f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDOneMember_7cb5597f-feee-41f0-80ac-28054f85d756" xlink:href="frt-20211231.xsd#frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_4141085a-4f8c-4556-8ad4-723464d6b3f4" xlink:to="loc_frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDOneMember_7cb5597f-feee-41f0-80ac-28054f85d756" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDTwoMember_b98ed1f9-0824-419e-8ad6-9849f9d00231" xlink:href="frt-20211231.xsd#frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_4141085a-4f8c-4556-8ad4-723464d6b3f4" xlink:to="loc_frt_SecondMortgageOnARetailShoppingCenterInRockvilleMDTwoMember_b98ed1f9-0824-419e-8ad6-9849f9d00231" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SecondMortgageOnARetailShoppingCenterInBaltimoreMDMember_24bd92ec-1954-4e6d-8f5c-1a69c41d2ae7" xlink:href="frt-20211231.xsd#frt_SecondMortgageOnARetailShoppingCenterInBaltimoreMDMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_4141085a-4f8c-4556-8ad4-723464d6b3f4" xlink:to="loc_frt_SecondMortgageOnARetailShoppingCenterInBaltimoreMDMember_24bd92ec-1954-4e6d-8f5c-1a69c41d2ae7" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
