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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:0e6db4ed-0777-412e-b57b-8e0a2142a64a,g:53485feb-f20f-484f-8566-25be78eb5873-->
<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/DocumentandEntityInformationDocument" xlink:type="simple" xlink:href="frt-20240331.xsd#DocumentandEntityInformationDocument"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DocumentandEntityInformationDocument" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_83c2bfd5-a4c2-4114-8faf-766180d83863" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntitiesTable_83c2bfd5-a4c2-4114-8faf-766180d83863" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_83c2bfd5-a4c2-4114-8faf-766180d83863" xlink:to="loc_dei_EntityListingsExchangeAxis_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04" xlink:to="loc_dei_ExchangeDomain_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_ad258dbc-e9ed-4f7b-8fef-50a842c33033" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_670ace2c-e82d-4f3d-a837-2bdcd1dfbb04" xlink:to="loc_dei_ExchangeDomain_ad258dbc-e9ed-4f7b-8fef-50a842c33033" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_5aeea133-8e9f-4129-8c18-ff17fbb593e1" xlink:href="https://xbrl.sec.gov/exch/2024/exch-2024.xsd#exch_XNYS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_ad258dbc-e9ed-4f7b-8fef-50a842c33033" xlink:to="loc_exch_XNYS_5aeea133-8e9f-4129-8c18-ff17fbb593e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_ebda20fd-3332-4130-8a81-7c49b6658104" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_83c2bfd5-a4c2-4114-8faf-766180d83863" xlink:to="loc_us-gaap_StatementClassOfStockAxis_ebda20fd-3332-4130-8a81-7c49b6658104" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ebda20fd-3332-4130-8a81-7c49b6658104_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ebda20fd-3332-4130-8a81-7c49b6658104" xlink:to="loc_us-gaap_ClassOfStockDomain_ebda20fd-3332-4130-8a81-7c49b6658104_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_df39f271-966d-4bdb-bb28-e44774700f17" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ebda20fd-3332-4130-8a81-7c49b6658104" xlink:to="loc_us-gaap_ClassOfStockDomain_df39f271-966d-4bdb-bb28-e44774700f17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_ff5c27cf-7e66-4762-a848-12118eb3c799" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_df39f271-966d-4bdb-bb28-e44774700f17" xlink:to="loc_us-gaap_CommonStockMember_ff5c27cf-7e66-4762-a848-12118eb3c799" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DepositarySharesMember_dfc7bd67-38dd-4444-b7ed-4a8b6981556e" xlink:href="frt-20240331.xsd#frt_DepositarySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_df39f271-966d-4bdb-bb28-e44774700f17" xlink:to="loc_frt_DepositarySharesMember_dfc7bd67-38dd-4444-b7ed-4a8b6981556e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_106fc387-74a8-48a1-acc6-556714a5b7f9" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_83c2bfd5-a4c2-4114-8faf-766180d83863" xlink:to="loc_dei_LegalEntityAxis_106fc387-74a8-48a1-acc6-556714a5b7f9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_106fc387-74a8-48a1-acc6-556714a5b7f9_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_106fc387-74a8-48a1-acc6-556714a5b7f9" xlink:to="loc_dei_EntityDomain_106fc387-74a8-48a1-acc6-556714a5b7f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5d0876a2-e338-4e7b-9971-37f0aae3c97c" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_106fc387-74a8-48a1-acc6-556714a5b7f9" xlink:to="loc_dei_EntityDomain_5d0876a2-e338-4e7b-9971-37f0aae3c97c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FederalRealtyOPLPMember_356ac217-5881-4f64-b4bc-0561c9ec89c9" xlink:href="frt-20240331.xsd#frt_FederalRealtyOPLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5d0876a2-e338-4e7b-9971-37f0aae3c97c" xlink:to="loc_frt_FederalRealtyOPLPMember_356ac217-5881-4f64-b4bc-0561c9ec89c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_31f12092-46ae-4b86-9e31-281fef73eccd" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentType_31f12092-46ae-4b86-9e31-281fef73eccd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_97e9bbd2-4e77-4f50-93cb-e530d3ed24a6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentQuarterlyReport_97e9bbd2-4e77-4f50-93cb-e530d3ed24a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_5cd5e001-1357-4def-9af1-091dc8f258a5" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentPeriodEndDate_5cd5e001-1357-4def-9af1-091dc8f258a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_ea2077e9-4b16-4b71-b6d6-cdd4494ea91b" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentTransitionReport_ea2077e9-4b16-4b71-b6d6-cdd4494ea91b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_8967634d-f68a-45e6-968a-38d62d523ed0" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityFileNumber_8967634d-f68a-45e6-968a-38d62d523ed0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_ee02eff8-7b6e-4a78-a355-6ad459d8f01e" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityRegistrantName_ee02eff8-7b6e-4a78-a355-6ad459d8f01e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_92256dab-85e6-4868-a232-8912fec284db" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityCentralIndexKey_92256dab-85e6-4868-a232-8912fec284db" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_fd2d980e-40fc-4f06-8797-8de033883cc5" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_CurrentFiscalYearEndDate_fd2d980e-40fc-4f06-8797-8de033883cc5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_8dc8eae3-b082-4619-a155-889bdb57cc39" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentFiscalYearFocus_8dc8eae3-b082-4619-a155-889bdb57cc39" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_d10e9762-d73a-4ae1-809c-091eb4d58350" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_DocumentFiscalPeriodFocus_d10e9762-d73a-4ae1-809c-091eb4d58350" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_7960d604-b93e-418c-8464-ad7be6675a35" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_AmendmentFlag_7960d604-b93e-418c-8464-ad7be6675a35" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_2c7022f6-d0f9-4986-bb03-1060febedd6c" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityIncorporationStateCountryCode_2c7022f6-d0f9-4986-bb03-1060febedd6c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_83493691-dec8-4b5f-a74b-c7196d7014c6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityTaxIdentificationNumber_83493691-dec8-4b5f-a74b-c7196d7014c6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_960cf529-15cb-4def-847d-18d4f04842d6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityAddressAddressLine1_960cf529-15cb-4def-847d-18d4f04842d6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_5d49b5be-339f-4900-8228-0da8e43bf32a" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityAddressCityOrTown_5d49b5be-339f-4900-8228-0da8e43bf32a" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_7477c30b-ecfa-40de-b359-fa0632cdfa55" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityAddressStateOrProvince_7477c30b-ecfa-40de-b359-fa0632cdfa55" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_a279f682-35f3-4565-b97e-5a90a53d4e24" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityAddressPostalZipCode_a279f682-35f3-4565-b97e-5a90a53d4e24" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_63201f5c-f54b-4734-a869-4eaa46be5d29" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_CityAreaCode_63201f5c-f54b-4734-a869-4eaa46be5d29" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_c3491030-42fb-4dfa-b5f4-d495d5e265d3" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_LocalPhoneNumber_c3491030-42fb-4dfa-b5f4-d495d5e265d3" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_3576e587-22bd-4247-b850-3eb39dfe164a" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_Security12bTitle_3576e587-22bd-4247-b850-3eb39dfe164a" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_6fe8f23c-a31f-4833-b584-235eb2a6963b" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_TradingSymbol_6fe8f23c-a31f-4833-b584-235eb2a6963b" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_6b61e14b-5030-48ac-b956-cf06da035251" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_SecurityExchangeName_6b61e14b-5030-48ac-b956-cf06da035251" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_d3c7ff2c-5adf-4aaf-93ba-96b04096dbf9" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityCurrentReportingStatus_d3c7ff2c-5adf-4aaf-93ba-96b04096dbf9" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_43b4b131-b0e3-4f5b-aaa0-29c725bfc44f" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityInteractiveDataCurrent_43b4b131-b0e3-4f5b-aaa0-29c725bfc44f" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_a07836d0-03d5-455a-bd66-56f8fbeb6762" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityFilerCategory_a07836d0-03d5-455a-bd66-56f8fbeb6762" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_e56cf5f9-1f0a-4e54-80e6-105dc681d65c" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntitySmallBusiness_e56cf5f9-1f0a-4e54-80e6-105dc681d65c" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_7714bbf7-4200-4f9f-9aa0-99c99c7754b8" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityEmergingGrowthCompany_7714bbf7-4200-4f9f-9aa0-99c99c7754b8" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_3e7476a2-24d6-4d08-8697-ec61c3c9871b" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityShellCompany_3e7476a2-24d6-4d08-8697-ec61c3c9871b" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_d7987566-a05d-483e-8e59-97da580383ec" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_55bb7dd2-8733-41f5-b31b-73d57185a3cb" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_d7987566-a05d-483e-8e59-97da580383ec" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_9458a4e2-b1f1-4d81-bce7-2a64b4775120" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_StatementTable_9458a4e2-b1f1-4d81-bce7-2a64b4775120" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_85608397-b787-4667-97df-7dc2a990b830" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9458a4e2-b1f1-4d81-bce7-2a64b4775120" xlink:to="loc_us-gaap_StatementClassOfStockAxis_85608397-b787-4667-97df-7dc2a990b830" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_85608397-b787-4667-97df-7dc2a990b830_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_85608397-b787-4667-97df-7dc2a990b830" xlink:to="loc_us-gaap_ClassOfStockDomain_85608397-b787-4667-97df-7dc2a990b830_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ed98c3ed-a402-463c-b530-147e026dbefe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_85608397-b787-4667-97df-7dc2a990b830" xlink:to="loc_us-gaap_ClassOfStockDomain_ed98c3ed-a402-463c-b530-147e026dbefe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_97d99592-8bf8-4a25-ad21-0d43210021bd" xlink:href="frt-20240331.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ed98c3ed-a402-463c-b530-147e026dbefe" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_97d99592-8bf8-4a25-ad21-0d43210021bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_b8f30793-5f5b-43f9-8ed6-c7e7168a74b9" xlink:href="frt-20240331.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ed98c3ed-a402-463c-b530-147e026dbefe" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_b8f30793-5f5b-43f9-8ed6-c7e7168a74b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_a71b296e-82d2-494f-a586-33e0fd8d99e1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9458a4e2-b1f1-4d81-bce7-2a64b4775120" xlink:to="loc_srt_ConsolidatedEntitiesAxis_a71b296e-82d2-494f-a586-33e0fd8d99e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_a71b296e-82d2-494f-a586-33e0fd8d99e1_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_a71b296e-82d2-494f-a586-33e0fd8d99e1" xlink:to="loc_srt_ConsolidatedEntitiesDomain_a71b296e-82d2-494f-a586-33e0fd8d99e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_812e059c-28c3-4011-aeeb-aa23cdb8f959" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_a71b296e-82d2-494f-a586-33e0fd8d99e1" xlink:to="loc_srt_ConsolidatedEntitiesDomain_812e059c-28c3-4011-aeeb-aa23cdb8f959" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_cc2e465a-8178-45fd-a3db-4fc62d02b02b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_812e059c-28c3-4011-aeeb-aa23cdb8f959" xlink:to="loc_srt_PartnershipInterestMember_cc2e465a-8178-45fd-a3db-4fc62d02b02b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RentalProperties_010702f6-5f01-4f4a-839e-ff045a43a3c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RentalProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_RentalProperties_010702f6-5f01-4f4a-839e-ff045a43a3c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressGross_2ffd990a-8c38-4627-8b2e-c725219ab337" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConstructionInProgressGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_ConstructionInProgressGross_2ffd990a-8c38-4627-8b2e-c725219ab337" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost_c9b81fca-449d-4d27-a4a7-61c7ce4b827f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAtCost_c9b81fca-449d-4d27-a4a7-61c7ce4b827f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_bd2e1461-61f6-4f58-99bd-18c97aa30e71" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_bd2e1461-61f6-4f58-99bd-18c97aa30e71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_38c00918-a6e4-4310-be63-7707caf49b19" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_38c00918-a6e4-4310-be63-7707caf49b19" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4bbb068b-2c7c-41a6-b76f-c067f17e3a1b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4bbb068b-2c7c-41a6-b76f-c067f17e3a1b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndNotesReceivableNet_e3c18c93-bf1b-4bcb-9f5e-7ede184beae5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsAndNotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_AccountsAndNotesReceivableNet_e3c18c93-bf1b-4bcb-9f5e-7ede184beae5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_ae8c2498-9902-4ceb-b071-50dd4b3ed843" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_ae8c2498-9902-4ceb-b071-50dd4b3ed843" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_cba23bfa-323b-4d16-82dd-b15f0dd00013" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_cba23bfa-323b-4d16-82dd-b15f0dd00013" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_a479655b-92a9-4c2c-acc3-d0b45c7de1d6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_a479655b-92a9-4c2c-acc3-d0b45c7de1d6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset_6da89a33-33ca-4a09-9b30-df44d9601395" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAsset_6da89a33-33ca-4a09-9b30-df44d9601395" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssets_b04eb13f-b485-419c-a9e8-61cf67a57a6e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PrepaidExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssets_b04eb13f-b485-419c-a9e8-61cf67a57a6e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_eee3dfae-f9ae-48c9-ad86-6d11c392fbc1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_de8dc2c2-e2a6-44a6-89c7-cff2b863be4a" xlink:to="loc_us-gaap_Assets_eee3dfae-f9ae-48c9-ad86-6d11c392fbc1" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_f1106eeb-985d-454b-b1b5-372399cb3d4d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_SecuredDebt_f1106eeb-985d-454b-b1b5-372399cb3d4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayable_b7a336fd-9546-465a-832f-471bbe8b34cc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_NotesPayable_b7a336fd-9546-465a-832f-471bbe8b34cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebt_bd937c65-807b-4de9-841b-c7f88a3c61ac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnsecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_UnsecuredDebt_bd937c65-807b-4de9-841b-c7f88a3c61ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_5ce46846-03e3-4635-a80e-9575c5f730b7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_5ce46846-03e3-4635-a80e-9575c5f730b7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_0207fb59-121c-492b-971f-fd5d8f257e71" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_0207fb59-121c-492b-971f-fd5d8f257e71" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDepositLiability_27f93f80-6c1a-4945-876f-ebd2c48d3fb2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecurityDepositLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_SecurityDepositLiability_27f93f80-6c1a-4945-876f-ebd2c48d3fb2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_830a577e-4ae7-413e-ae46-1dcb56e34dee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_OperatingLeaseLiability_830a577e-4ae7-413e-ae46-1dcb56e34dee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_cd958068-7900-4f0a-b195-78c178a95914" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_FinanceLeaseLiability_cd958068-7900-4f0a-b195-78c178a95914" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCreditsAndOtherLiabilities_8a8c5e1c-13ef-49f1-8987-b346b662a79a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredCreditsAndOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_DeferredCreditsAndOtherLiabilities_8a8c5e1c-13ef-49f1-8987-b346b662a79a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_f810c84a-1b46-4e47-b0d4-e5bfd7573e4e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_9282f518-e856-4c4a-824c-d39c07aca48b" xlink:to="loc_us-gaap_Liabilities_f810c84a-1b46-4e47-b0d4-e5bfd7573e4e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_69eb8acc-ec53-43bf-8e0a-21be4db2f8e9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_CommitmentsAndContingencies_69eb8acc-ec53-43bf-8e0a-21be4db2f8e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_bd671e6d-cdb4-46b7-b44f-64920b306c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_bd671e6d-cdb4-46b7-b44f-64920b306c3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_35632c88-5d80-4092-a0aa-7eb85ecff693" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_PreferredStockValue_35632c88-5d80-4092-a0aa-7eb85ecff693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_b42a875c-8b84-426a-aa1c-a2b14d285397" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_CommonStockValue_b42a875c-8b84-426a-aa1c-a2b14d285397" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_f8096818-2a73-4e39-b236-cfc29e406afb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_f8096818-2a73-4e39-b236-cfc29e406afb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_f30e1d04-b886-448d-b5f9-9718d99090cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_f30e1d04-b886-448d-b5f9-9718d99090cb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_9b98a9f3-fc6f-4adf-a816-3dd0edbdeed8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_9b98a9f3-fc6f-4adf-a816-3dd0edbdeed8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_cd39b60b-40fe-4c04-b9cb-a87cd43e76cd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_StockholdersEquity_cd39b60b-40fe-4c04-b9cb-a87cd43e76cd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_1824f745-6d7a-4dd3-8d19-b7d6bf2c6d7d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_MinorityInterest_1824f745-6d7a-4dd3-8d19-b7d6bf2c6d7d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_b4c5673c-ae16-4844-af8f-bd508ccda614" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_bf9c4f22-8618-49fd-98f2-494b80c7e172" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_b4c5673c-ae16-4844-af8f-bd508ccda614" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsPreferredPartnersCapitalAccounts_945d0794-4323-4747-8094-f57ff62f20d8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredUnitsPreferredPartnersCapitalAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:to="loc_us-gaap_PreferredUnitsPreferredPartnersCapitalAccounts_945d0794-4323-4747-8094-f57ff62f20d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonUnitsCapitalAccounts_df2f02d5-bb4c-44a5-b0ca-29d9b61bcda7" xlink:href="frt-20240331.xsd#frt_CommonUnitsCapitalAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:to="loc_frt_CommonUnitsCapitalAccounts_df2f02d5-bb4c-44a5-b0ca-29d9b61bcda7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f35e9c5e-2b22-4f0d-8b1a-170daeadd5da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_f63499eb-4012-498b-82ed-a1e6b1764453" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:to="loc_us-gaap_PartnersCapital_f63499eb-4012-498b-82ed-a1e6b1764453" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_ece01f26-bcac-4121-b21b-d132610366a5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:to="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_ece01f26-bcac-4121-b21b-d132610366a5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_5dff5b2a-cd68-42b4-94a7-36063b553a2b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalAbstract_d06000db-5510-4c47-a317-25456f272c53" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_5dff5b2a-cd68-42b4-94a7-36063b553a2b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae56fa66-d13d-430f-964a-f3270b3f858d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e763ee1f-b3b8-4c31-9c4b-8fd3ae29b1e2" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae56fa66-d13d-430f-964a-f3270b3f858d" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedBalanceSheetsParentheticals" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedBalanceSheetsParentheticals"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedBalanceSheetsParentheticals" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_159f5df0-ae33-40fb-8708-719311043dca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_StatementTable_159f5df0-ae33-40fb-8708-719311043dca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_040c9132-2817-4146-b785-7d7eb275b3a7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_159f5df0-ae33-40fb-8708-719311043dca" xlink:to="loc_us-gaap_StatementClassOfStockAxis_040c9132-2817-4146-b785-7d7eb275b3a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_040c9132-2817-4146-b785-7d7eb275b3a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_040c9132-2817-4146-b785-7d7eb275b3a7" xlink:to="loc_us-gaap_ClassOfStockDomain_040c9132-2817-4146-b785-7d7eb275b3a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_b18abc3d-e1f9-4c35-a210-ba065733f14c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_040c9132-2817-4146-b785-7d7eb275b3a7" xlink:to="loc_us-gaap_ClassOfStockDomain_b18abc3d-e1f9-4c35-a210-ba065733f14c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_74a41402-f858-4b4c-9d12-1b697e7ac0c2" xlink:href="frt-20240331.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_b18abc3d-e1f9-4c35-a210-ba065733f14c" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_74a41402-f858-4b4c-9d12-1b697e7ac0c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_4091bf2d-85f8-4315-abf5-eaf945af4b0c" xlink:href="frt-20240331.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_b18abc3d-e1f9-4c35-a210-ba065733f14c" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_4091bf2d-85f8-4315-abf5-eaf945af4b0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_f4865af7-5e55-4c5e-985c-7be6c776f140" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_159f5df0-ae33-40fb-8708-719311043dca" xlink:to="loc_srt_ConsolidatedEntitiesAxis_f4865af7-5e55-4c5e-985c-7be6c776f140" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_f4865af7-5e55-4c5e-985c-7be6c776f140_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_f4865af7-5e55-4c5e-985c-7be6c776f140" xlink:to="loc_srt_ConsolidatedEntitiesDomain_f4865af7-5e55-4c5e-985c-7be6c776f140_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_3c0fe97d-85b7-457e-9a2c-bb0b3020999c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_f4865af7-5e55-4c5e-985c-7be6c776f140" xlink:to="loc_srt_ConsolidatedEntitiesDomain_3c0fe97d-85b7-457e-9a2c-bb0b3020999c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_f65a9e94-5a33-4142-9241-42d5852a416e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_3c0fe97d-85b7-457e-9a2c-bb0b3020999c" xlink:to="loc_srt_PartnershipInterestMember_f65a9e94-5a33-4142-9241-42d5852a416e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OperatingRealEstateFromConsolidatedVariableInterestEntities_5719f814-437b-4565-9064-d5f069b54607" xlink:href="frt-20240331.xsd#frt_OperatingRealEstateFromConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_frt_OperatingRealEstateFromConsolidatedVariableInterestEntities_5719f814-437b-4565-9064-d5f069b54607" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Constructioninprogresofconsolidatedvariableieestentity_322243d8-763d-43e2-bbd9-6f620800a738" xlink:href="frt-20240331.xsd#frt_Constructioninprogresofconsolidatedvariableieestentity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_frt_Constructioninprogresofconsolidatedvariableieestentity_322243d8-763d-43e2-bbd9-6f620800a738" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities_8d477577-ad36-460a-b324-2377a8fad64a" xlink:href="frt-20240331.xsd#frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_frt_AccumulatedDepreciationAndAmortizationConsolidatedVariableInterestEntities_8d477577-ad36-460a-b324-2377a8fad64a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_2dec207b-cf88-484e-9d96-c254a57e4fa3" xlink:href="frt-20240331.xsd#frt_MortgagePayableFromConsolidatedVariableInterestEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_frt_MortgagePayableFromConsolidatedVariableInterestEntities_2dec207b-cf88-484e-9d96-c254a57e4fa3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_feff00f8-af55-4a6b-8191-e36ba569d65a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_feff00f8-af55-4a6b-8191-e36ba569d65a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_8cecd813-2144-44a9-94ba-ed91c63e69f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_8cecd813-2144-44a9-94ba-ed91c63e69f1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_08287b63-a068-45c6-92a6-40a9df770662" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_08287b63-a068-45c6-92a6-40a9df770662" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_d62ec90f-0c2d-476c-a06b-cd4fed459320" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockLiquidationPreference_d62ec90f-0c2d-476c-a06b-cd4fed459320" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_0a0c8b2f-db85-4ab0-aba9-b7c34988b8f5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockSharesIssued_0a0c8b2f-db85-4ab0-aba9-b7c34988b8f5" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_d64d52b3-2e22-41f4-a0a7-430617e580b9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_d64d52b3-2e22-41f4-a0a7-430617e580b9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_83dad649-d508-459a-8e28-5ae903e0ac90" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_83dad649-d508-459a-8e28-5ae903e0ac90" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_332350a9-5962-4781-86ac-22c5eba8fec4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonStockSharesIssued_332350a9-5962-4781-86ac-22c5eba8fec4" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_5cec6f1d-2c41-4cd9-9465-33e86cf7bef1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_5cec6f1d-2c41-4cd9-9465-33e86cf7bef1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_a5c97240-ccb3-4f1c-89be-b9523fa5601c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_a5c97240-ccb3-4f1c-89be-b9523fa5601c" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsIssued_396fc522-3a13-4fab-9af7-1e0397a199b1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredUnitsIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredUnitsIssued_396fc522-3a13-4fab-9af7-1e0397a199b1" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredUnitsOutstanding_a46aefa6-f8df-4753-ab23-e9cc5773ccdd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_PreferredUnitsOutstanding_a46aefa6-f8df-4753-ab23-e9cc5773ccdd" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonUnitIssued_93eb9d9a-8b6a-444e-bf18-553cf8ff4391" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonUnitIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonUnitIssued_93eb9d9a-8b6a-444e-bf18-553cf8ff4391" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonUnitOutstanding_045f614c-56f5-4470-8cea-d43df7d74b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonUnitOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_54257405-ae4b-42c1-a537-3baae330b9ff" xlink:to="loc_us-gaap_CommonUnitOutstanding_045f614c-56f5-4470-8cea-d43df7d74b9f" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedStatementsOfComprehensiveIncome"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_deb8487c-aa37-4f32-b5f8-1e972c88cd91" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_StatementTable_deb8487c-aa37-4f32-b5f8-1e972c88cd91" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_ef0804d9-b87e-41ef-803a-2e625bdd71ba" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_deb8487c-aa37-4f32-b5f8-1e972c88cd91" xlink:to="loc_srt_ConsolidatedEntitiesAxis_ef0804d9-b87e-41ef-803a-2e625bdd71ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_ef0804d9-b87e-41ef-803a-2e625bdd71ba_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_ef0804d9-b87e-41ef-803a-2e625bdd71ba" xlink:to="loc_srt_ConsolidatedEntitiesDomain_ef0804d9-b87e-41ef-803a-2e625bdd71ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_4fa7d4d0-0910-4af5-a513-c2573337c9a5" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_ef0804d9-b87e-41ef-803a-2e625bdd71ba" xlink:to="loc_srt_ConsolidatedEntitiesDomain_4fa7d4d0-0910-4af5-a513-c2573337c9a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_45ff06cd-f184-45a5-9872-de070c2f3088" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_4fa7d4d0-0910-4af5-a513-c2573337c9a5" xlink:to="loc_srt_PartnershipInterestMember_45ff06cd-f184-45a5-9872-de070c2f3088" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_620f1aab-6b56-4ce7-b9f4-ac545396e0db" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_RevenuesAbstract_620f1aab-6b56-4ce7-b9f4-ac545396e0db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_1b2101a0-627d-4b62-81f9-8ea07c502c28" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_620f1aab-6b56-4ce7-b9f4-ac545396e0db" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_1b2101a0-627d-4b62-81f9-8ea07c502c28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RevenueMortgageInterest_d36028be-e1de-4e46-bad8-53b7240ccf2b" xlink:href="frt-20240331.xsd#frt_RevenueMortgageInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_620f1aab-6b56-4ce7-b9f4-ac545396e0db" xlink:to="loc_frt_RevenueMortgageInterest_d36028be-e1de-4e46-bad8-53b7240ccf2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_93a542c2-665e-44d6-9894-62579cb29cbe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_620f1aab-6b56-4ce7-b9f4-ac545396e0db" xlink:to="loc_us-gaap_Revenues_93a542c2-665e-44d6-9894-62579cb29cbe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_b2aeeb4c-799f-4ea3-8031-824fa988c381" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_b2aeeb4c-799f-4ea3-8031-824fa988c381" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTaxExpense_1d082e2e-ede0-4d75-b15c-107b5bf291ba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateTaxExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_us-gaap_RealEstateTaxExpense_1d082e2e-ede0-4d75-b15c-107b5bf291ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_3e203c45-cfbb-4dc3-83b0-d84a4ad34d60" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_3e203c45-cfbb-4dc3-83b0-d84a4ad34d60" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_c1b1c77d-8da4-4504-a560-d22043d63c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_us-gaap_DepreciationAndAmortization_c1b1c77d-8da4-4504-a560-d22043d63c6c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_3f87a250-1a5f-4d07-bd03-89a2e08799e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_us-gaap_OperatingExpenses_3f87a250-1a5f-4d07-bd03-89a2e08799e4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GainOnSaleOfRealEstate_23f3206b-c3f1-47aa-837c-b37c1b26997b" xlink:href="frt-20240331.xsd#frt_GainOnSaleOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ecbb884-a9dd-4d14-ad95-5df99a97e3dc" xlink:to="loc_frt_GainOnSaleOfRealEstate_23f3206b-c3f1-47aa-837c-b37c1b26997b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_7abfbc31-82d9-4c47-9e13-1ddf1b01a280" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_OperatingIncomeLoss_7abfbc31-82d9-4c47-9e13-1ddf1b01a280" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncomeAndExpensesAbstract_40a5fffd-6544-4ef7-b479-53a50406c8bc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherIncomeAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_OtherIncomeAndExpensesAbstract_40a5fffd-6544-4ef7-b479-53a50406c8bc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeOther_de859862-6080-4d30-8620-f9cee9671c0e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestIncomeOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_40a5fffd-6544-4ef7-b479-53a50406c8bc" xlink:to="loc_us-gaap_InterestIncomeOther_de859862-6080-4d30-8620-f9cee9671c0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_4655507f-55c7-4ac7-88d2-2385aa11a8b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_40a5fffd-6544-4ef7-b479-53a50406c8bc" xlink:to="loc_us-gaap_InterestExpense_4655507f-55c7-4ac7-88d2-2385aa11a8b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3688b181-0c64-48bb-9bf1-6fc8d1763085" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_40a5fffd-6544-4ef7-b479-53a50406c8bc" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3688b181-0c64-48bb-9bf1-6fc8d1763085" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_b554550a-be1f-4166-951e-d54e551d09ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_ProfitLoss_b554550a-be1f-4166-951e-d54e551d09ec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_f395e259-6705-454d-851f-7f6fc1175d51" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_f395e259-6705-454d-851f-7f6fc1175d51" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_e5d23a65-75c5-4fd4-a178-2fc2dea54a7a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_NetIncomeLoss_e5d23a65-75c5-4fd4-a178-2fc2dea54a7a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_bf5e9a2d-a930-4e47-bc16-8c0183c654e3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_bf5e9a2d-a930-4e47-bc16-8c0183c654e3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DistributionsDeclaredToPreferredUnitHolders_8cf72007-670d-4ca8-a0c8-887c489107ba" xlink:href="frt-20240331.xsd#frt_DistributionsDeclaredToPreferredUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_frt_DistributionsDeclaredToPreferredUnitHolders_8cf72007-670d-4ca8-a0c8-887c489107ba" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_57d2ac84-e2ba-48d8-bcd9-d9b90f5db47d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_57d2ac84-e2ba-48d8-bcd9-d9b90f5db47d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAllocatedToGeneralPartners_b838d089-3eef-404a-946d-959576d75fac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAllocatedToGeneralPartners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_NetIncomeLossAllocatedToGeneralPartners_b838d089-3eef-404a-946d-959576d75fac" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_faf263fb-57cb-4694-b1e3-c33d66f3d1c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:to="loc_us-gaap_EarningsPerShareBasic_faf263fb-57cb-4694-b1e3-c33d66f3d1c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_f264d44e-37bd-4d31-a79e-928da65a4e64" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:to="loc_us-gaap_EarningsPerShareDiluted_f264d44e-37bd-4d31-a79e-928da65a4e64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_a04e3a2d-2150-4555-8e04-5f85a7704c68" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_a04e3a2d-2150-4555-8e04-5f85a7704c68" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_a98aa165-2373-4d60-bf05-6255652688d8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_c71d97bb-5f0e-4426-b693-e678e0ae8d03" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_a98aa165-2373-4d60-bf05-6255652688d8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:href="frt-20240331.xsd#frt_EARNINGSPERCOMMONUNITBASICAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax_0de05e6d-3422-4987-b3e1-c3afdf1571c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax_0de05e6d-3422-4987-b3e1-c3afdf1571c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax_c2adad29-7a16-40e8-980e-f661680d5bff" xlink:href="frt-20240331.xsd#frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:to="loc_frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax_c2adad29-7a16-40e8-980e-f661680d5bff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic_7eaa47ab-939f-4ea4-8f29-34b35b880ced" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic_7eaa47ab-939f-4ea4-8f29-34b35b880ced" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WeightedAverageCommonUnitsOutstandingDiluted_41ab3f49-d47a-454a-8cbb-51dd9603e83a" xlink:href="frt-20240331.xsd#frt_WeightedAverageCommonUnitsOutstandingDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_dd56f0a4-68cd-469a-a402-320f36e95ccb" xlink:to="loc_frt_WeightedAverageCommonUnitsOutstandingDiluted_41ab3f49-d47a-454a-8cbb-51dd9603e83a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_120da3b6-9c68-4ac8-b489-7d2d28ce98b9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_af391cfb-6de2-4ff5-8964-85334234a22e" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_120da3b6-9c68-4ac8-b489-7d2d28ce98b9" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_61a87825-67e0-455b-bdcb-c46f9409cbf8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_120da3b6-9c68-4ac8-b489-7d2d28ce98b9" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_61a87825-67e0-455b-bdcb-c46f9409cbf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_abbecc22-cdd2-4173-9f2b-3b8ccb99ea35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_120da3b6-9c68-4ac8-b489-7d2d28ce98b9" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_abbecc22-cdd2-4173-9f2b-3b8ccb99ea35" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementOfShareholdersEquity" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedStatementOfShareholdersEquity"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementOfShareholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_82c63e29-541c-4ad9-919f-9bb888a499ea" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c7ee8383-4135-4f46-8778-f80566f60c01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_82c63e29-541c-4ad9-919f-9bb888a499ea" xlink:to="loc_us-gaap_StatementTable_c7ee8383-4135-4f46-8778-f80566f60c01" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4b21260d-0b05-46a1-808a-780dabc711a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c7ee8383-4135-4f46-8778-f80566f60c01" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4b21260d-0b05-46a1-808a-780dabc711a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_4b21260d-0b05-46a1-808a-780dabc711a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4b21260d-0b05-46a1-808a-780dabc711a8" xlink:to="loc_us-gaap_ClassOfStockDomain_4b21260d-0b05-46a1-808a-780dabc711a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_d697bb04-8385-4422-aab3-59836e7b7469" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4b21260d-0b05-46a1-808a-780dabc711a8" xlink:to="loc_us-gaap_ClassOfStockDomain_d697bb04-8385-4422-aab3-59836e7b7469" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_9e8338d5-f296-4ecf-916b-e65c4e6255a7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_d697bb04-8385-4422-aab3-59836e7b7469" xlink:to="loc_us-gaap_PreferredStockMember_9e8338d5-f296-4ecf-916b-e65c4e6255a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_acdb47c6-35ff-459b-8582-d7a44b5cbbe9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_d697bb04-8385-4422-aab3-59836e7b7469" xlink:to="loc_us-gaap_CommonStockMember_acdb47c6-35ff-459b-8582-d7a44b5cbbe9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_29f7073d-96bb-4558-90c4-92da0d9ec75d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c7ee8383-4135-4f46-8778-f80566f60c01" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_29f7073d-96bb-4558-90c4-92da0d9ec75d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_29f7073d-96bb-4558-90c4-92da0d9ec75d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_29f7073d-96bb-4558-90c4-92da0d9ec75d" xlink:to="loc_us-gaap_EquityComponentDomain_29f7073d-96bb-4558-90c4-92da0d9ec75d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_29f7073d-96bb-4558-90c4-92da0d9ec75d" xlink:to="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_18a0b558-0431-4d2f-ac66-b1ff4a211ec5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_PreferredStockMember_18a0b558-0431-4d2f-ac66-b1ff4a211ec5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_88a573d9-07cc-4dfb-a09a-f7141d1e8ef7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_CommonStockMember_88a573d9-07cc-4dfb-a09a-f7141d1e8ef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_656076ec-3253-4410-9768-2fba525f680f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_656076ec-3253-4410-9768-2fba525f680f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_6b5c1733-23a7-41c1-9a18-ed9976dd78b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_6b5c1733-23a7-41c1-9a18-ed9976dd78b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b5f023be-915c-4373-9a7e-b566668007b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b5f023be-915c-4373-9a7e-b566668007b2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_1966f733-2921-4127-a89f-98d489020a46" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5409b973-2ea8-4f8b-b4f3-c37a91e5119c" xlink:to="loc_us-gaap_NoncontrollingInterestMember_1966f733-2921-4127-a89f-98d489020a46" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeAxis_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c7ee8383-4135-4f46-8778-f80566f60c01" xlink:to="loc_frt_ConvertibleUnitTypeAxis_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3_default" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ConvertibleUnitTypeAxis_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3" xlink:to="loc_frt_ConvertibleUnitTypeDomain_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_df128c8b-db50-4f30-a1fd-8459735315f7" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ConvertibleUnitTypeAxis_e84cb74c-4a1d-477b-93cf-619ea5e1a2f3" xlink:to="loc_frt_ConvertibleUnitTypeDomain_df128c8b-db50-4f30-a1fd-8459735315f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DownREITOPUnitsMember_95c29f30-e0d2-444d-a7d2-9dbf852e6ef2" xlink:href="frt-20240331.xsd#frt_DownREITOPUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ConvertibleUnitTypeDomain_df128c8b-db50-4f30-a1fd-8459735315f7" xlink:to="loc_frt_DownREITOPUnitsMember_95c29f30-e0d2-444d-a7d2-9dbf852e6ef2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_82c63e29-541c-4ad9-919f-9bb888a499ea" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_8ec3717e-fb04-4d58-9278-e7dbcf89b7bc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_SharesOutstanding_8ec3717e-fb04-4d58-9278-e7dbcf89b7bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9c84b077-344c-4bb6-a5f2-615409166068" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9c84b077-344c-4bb6-a5f2-615409166068" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_2f9b65c2-86f5-4804-9737-f9fcffce5851" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_2f9b65c2-86f5-4804-9737-f9fcffce5851" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_6a6fcf07-4cc7-4d47-818d-c6805ea5083a" xlink:href="frt-20240331.xsd#frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_6a6fcf07-4cc7-4d47-818d-c6805ea5083a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_22e9225c-387d-4feb-a30c-ff64b262913f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_DividendsCommonStockCash_22e9225c-387d-4feb-a30c-ff64b262913f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStockCash_94687f1d-688f-4bb3-91d6-504925e013d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPreferredStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_DividendsPreferredStockCash_94687f1d-688f-4bb3-91d6-504925e013d9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_4893af00-59c8-4237-885d-342da557c8a9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_4893af00-59c8-4237-885d-342da557c8a9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_507739c8-04b0-4732-8052-3c1c850ec002" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_507739c8-04b0-4732-8052-3c1c850ec002" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_bd46dd19-8c48-46d9-9b37-9bf9234857fc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_bd46dd19-8c48-46d9-9b37-9bf9234857fc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_1f885f65-e3e8-47e2-aa00-88f2a25d06da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan_1f885f65-e3e8-47e2-aa00-88f2a25d06da" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan_9453e15e-54f5-4175-91c6-acb3d837f7c0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan_9453e15e-54f5-4175-91c6-acb3d837f7c0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareBasedCompensationExpenseNetShares_d87a5126-c2b5-4361-8465-5191dfc3ddbd" xlink:href="frt-20240331.xsd#frt_ShareBasedCompensationExpenseNetShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_frt_ShareBasedCompensationExpenseNetShares_d87a5126-c2b5-4361-8465-5191dfc3ddbd" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareBasedCompensationExpenseNetValue_db377c08-d2db-4d77-9145-e175734526cf" xlink:href="frt-20240331.xsd#frt_ShareBasedCompensationExpenseNetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_frt_ShareBasedCompensationExpenseNetValue_db377c08-d2db-4d77-9145-e175734526cf" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_c358d806-0e25-4d19-a110-a23d33add469" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_c358d806-0e25-4d19-a110-a23d33add469" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_ec52081e-a5b6-4248-b883-a1f061f0ebca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_ec52081e-a5b6-4248-b883-a1f061f0ebca" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_12bf18b1-a094-4492-a062-5e9d5e941dac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_12bf18b1-a094-4492-a062-5e9d5e941dac" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_08f2d7c3-48b4-40da-9392-9f884fd98ee1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_08f2d7c3-48b4-40da-9392-9f884fd98ee1" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_2b61a28b-e5bf-4884-80e7-cc449c030b30" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_2b61a28b-e5bf-4884-80e7-cc449c030b30" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Contributionsfromnoncontrollinginterests_72c228a6-0931-479b-8bb0-be67ef926cf7" xlink:href="frt-20240331.xsd#frt_Contributionsfromnoncontrollinginterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_frt_Contributionsfromnoncontrollinginterests_72c228a6-0931-479b-8bb0-be67ef926cf7" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CappedCallPremium_c440340e-cb95-4fd7-9506-fd2e84dd4b29" xlink:href="frt-20240331.xsd#frt_CappedCallPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3480911e-0fec-44b3-949a-069abe9a9bca" xlink:to="loc_frt_CappedCallPremium_c440340e-cb95-4fd7-9506-fd2e84dd4b29" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_24d31881-c06c-4162-b547-c08577bb6307" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_076a21f3-71e6-431f-8031-b3e2801f76d4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedStatementsOfCashFlows"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_e712b52f-fa42-43e8-9f59-3c4bea6596bd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_StatementTable_e712b52f-fa42-43e8-9f59-3c4bea6596bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_2e67a3e3-a437-4f11-8946-e14b542a1a8f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_e712b52f-fa42-43e8-9f59-3c4bea6596bd" xlink:to="loc_srt_ConsolidatedEntitiesAxis_2e67a3e3-a437-4f11-8946-e14b542a1a8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_2e67a3e3-a437-4f11-8946-e14b542a1a8f_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_2e67a3e3-a437-4f11-8946-e14b542a1a8f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_2e67a3e3-a437-4f11-8946-e14b542a1a8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_ad2a8b54-34e0-43a6-9ada-8fb5d324c214" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_2e67a3e3-a437-4f11-8946-e14b542a1a8f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_ad2a8b54-34e0-43a6-9ada-8fb5d324c214" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_b486e731-ad3c-4da7-8d9a-4eb335480dca" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_ad2a8b54-34e0-43a6-9ada-8fb5d324c214" xlink:to="loc_srt_PartnershipInterestMember_b486e731-ad3c-4da7-8d9a-4eb335480dca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_e74c51c9-ea1e-4e62-af89-0bfdfb226be4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:to="loc_us-gaap_ProfitLoss_e74c51c9-ea1e-4e62-af89-0bfdfb226be4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AdjustmentDepreciationAndAmortization_494bb5ac-08cb-4575-b7c1-8746e6d45aaa" xlink:href="frt-20240331.xsd#frt_AdjustmentDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_frt_AdjustmentDepreciationAndAmortization_494bb5ac-08cb-4575-b7c1-8746e6d45aaa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_GainOnSaleOfRealEstate_319764ae-a2ce-463e-8e21-c8523e8f1713" xlink:href="frt-20240331.xsd#frt_GainOnSaleOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_frt_GainOnSaleOfRealEstate_319764ae-a2ce-463e-8e21-c8523e8f1713" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3affa8a4-48c4-4bb0-9b8e-c025ac57039e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3affa8a4-48c4-4bb0-9b8e-c025ac57039e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StraightLineRent_f47211cd-092a-4545-a993-a3f5d5904d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StraightLineRent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_us-gaap_StraightLineRent_f47211cd-092a-4545-a993-a3f5d5904d9e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_20b60ca3-c427-45e0-a370-e5d5bd4c3d4d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_us-gaap_ShareBasedCompensation_20b60ca3-c427-45e0-a370-e5d5bd4c3d4d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_711b7657-f012-479b-b05d-b89a4337dbcf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6e54aed9-308e-4972-a351-8fc4c2171157" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_711b7657-f012-479b-b05d-b89a4337dbcf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_f5d81a83-823e-4fcc-8339-8bebae27a1c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_f5d81a83-823e-4fcc-8339-8bebae27a1c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_8ac63ec0-5d68-4f9d-93b8-20bca8875cc8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_8ac63ec0-5d68-4f9d-93b8-20bca8875cc8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_ac2b4054-ac38-4579-90b0-0d285684881a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_ac2b4054-ac38-4579-90b0-0d285684881a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_IncreaseDecreaseInSecurityDepositsAndOtherLiabilities_599a58ca-6732-464e-8ee4-179644b05107" xlink:href="frt-20240331.xsd#frt_IncreaseDecreaseInSecurityDepositsAndOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_eaacaf17-f5a2-42de-848e-37a8ba07134f" xlink:to="loc_frt_IncreaseDecreaseInSecurityDepositsAndOtherLiabilities_599a58ca-6732-464e-8ee4-179644b05107" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_fe0bcd0c-1a65-4d91-b0b4-ee7e74d16731" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0eb0869d-b935-4cee-bd79-cae0b5ab0acd" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_fe0bcd0c-1a65-4d91-b0b4-ee7e74d16731" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireRealEstate_e7f1653e-6bc4-435e-ab8c-3a4ab782a177" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToAcquireRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_us-gaap_PaymentsToAcquireRealEstate_e7f1653e-6bc4-435e-ab8c-3a4ab782a177" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CapitalExpendituresDevelopmentRedevelopment_9b001dca-4ea6-49f8-bdba-6d4b3367d17f" xlink:href="frt-20240331.xsd#frt_CapitalExpendituresDevelopmentRedevelopment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_frt_CapitalExpendituresDevelopmentRedevelopment_9b001dca-4ea6-49f8-bdba-6d4b3367d17f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CapitalExpendituresOther_4f9ac078-05de-4e70-844d-a96e67cc51ee" xlink:href="frt-20240331.xsd#frt_CapitalExpendituresOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_frt_CapitalExpendituresOther_4f9ac078-05de-4e70-844d-a96e67cc51ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRealEstateAndRealEstateJointVentures_a0d8937c-ebee-43c9-ba13-2171ab36cc0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromRealEstateAndRealEstateJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_us-gaap_ProceedsFromRealEstateAndRealEstateJointVentures_a0d8937c-ebee-43c9-ba13-2171ab36cc0b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDistributionsReceivedFromRealEstatePartnerships_f240d40c-f70c-448b-93fb-31928dbc8b3e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromDistributionsReceivedFromRealEstatePartnerships"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_us-gaap_ProceedsFromDistributionsReceivedFromRealEstatePartnerships_f240d40c-f70c-448b-93fb-31928dbc8b3e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInLeaseAcquisitionCosts_c7f386e4-27e8-4258-85ea-400a12cba739" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInLeaseAcquisitionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_us-gaap_IncreaseDecreaseInLeaseAcquisitionCosts_c7f386e4-27e8-4258-85ea-400a12cba739" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_29c97104-0173-4275-8740-49b2a38e67f7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1dc46f27-36a9-4b94-b7a9-e8c79eb25f07" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_29c97104-0173-4275-8740-49b2a38e67f7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfLinesOfCredit_fa791c80-a4d1-4718-93f2-3e1951e166d5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromRepaymentsOfLinesOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfLinesOfCredit_fa791c80-a4d1-4718-93f2-3e1951e166d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_87f7287a-a2cf-43de-9cbe-de9da7f2894b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_87f7287a-a2cf-43de-9cbe-de9da7f2894b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSeniorDebt_6e279a3b-7859-4019-be9c-9a95bbcb9c9f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RepaymentsOfSeniorDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_RepaymentsOfSeniorDebt_6e279a3b-7859-4019-be9c-9a95bbcb9c9f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CostsToExtendAndIssueNotesPayableAndMortgages_62f2cd1f-505d-4cd4-81db-ca2b34625c3e" xlink:href="frt-20240331.xsd#frt_CostsToExtendAndIssueNotesPayableAndMortgages"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_CostsToExtendAndIssueNotesPayableAndMortgages_62f2cd1f-505d-4cd4-81db-ca2b34625c3e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RepaymentOfMortgagesFinanceLeasesAndNotesPayable_d27c5235-5fa4-4dba-b14f-96bbe3ab55ad" xlink:href="frt-20240331.xsd#frt_RepaymentOfMortgagesFinanceLeasesAndNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_RepaymentOfMortgagesFinanceLeasesAndNotesPayable_d27c5235-5fa4-4dba-b14f-96bbe3ab55ad" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PurchaseOfCappedCalls_3bc2c8cd-3253-4106-90c7-40f2f28716c8" xlink:href="frt-20240331.xsd#frt_PurchaseOfCappedCalls"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_PurchaseOfCappedCalls_3bc2c8cd-3253-4106-90c7-40f2f28716c8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_1adf8ee8-da34-4d6b-9d70-5ed051ab76cc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_1adf8ee8-da34-4d6b-9d70-5ed051ab76cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_IssuanceOfCommonUnitsNetOfCosts_3864f252-3673-4f60-85d6-c504dd7f631f" xlink:href="frt-20240331.xsd#frt_IssuanceOfCommonUnitsNetOfCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_IssuanceOfCommonUnitsNetOfCosts_3864f252-3673-4f60-85d6-c504dd7f631f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DividendsPaidToCommonAndPreferredShareholders_caf44b83-c47e-4aab-b04f-9fe02261c650" xlink:href="frt-20240331.xsd#frt_DividendsPaidToCommonAndPreferredShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_DividendsPaidToCommonAndPreferredShareholders_caf44b83-c47e-4aab-b04f-9fe02261c650" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DividendsPaidToCommonAndPreferredUnitHolders_46b4e5a7-c536-4b95-896c-6911767f9a5c" xlink:href="frt-20240331.xsd#frt_DividendsPaidToCommonAndPreferredUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_DividendsPaidToCommonAndPreferredUnitHolders_46b4e5a7-c536-4b95-896c-6911767f9a5c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_2757ecdd-800e-498e-aec1-bb573e45c739" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_2757ecdd-800e-498e-aec1-bb573e45c739" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_bc729d4c-703b-410f-a414-9556518ace73" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_bc729d4c-703b-410f-a414-9556518ace73" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Paymentsofdividendsandredemptionsminorityinterest_025e953a-181d-4fe8-a676-213ba6ee0939" xlink:href="frt-20240331.xsd#frt_Paymentsofdividendsandredemptionsminorityinterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_frt_Paymentsofdividendsandredemptionsminorityinterest_025e953a-181d-4fe8-a676-213ba6ee0939" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_73c7db26-1211-41a9-923d-c7225e9860eb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_78eed4b0-ed15-481b-9a52-e2e9c67850fb" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_73c7db26-1211-41a9-923d-c7225e9860eb" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_d2ea9d0e-67bc-4e76-9f87-489f5cdd322e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_d2ea9d0e-67bc-4e76-9f87-489f5cdd322e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_305ba275-9e72-4e7e-abc9-ca078a31f26b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d3b0c28e-a0f6-428c-85b1-f7b1c4b80d08" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_305ba275-9e72-4e7e-abc9-ca078a31f26b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_aa083c0d-1aaa-4404-8248-b755ca4b8e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementsofCapital" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedStatementsofCapital"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementsofCapital" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_fbd5bd6f-3555-4df3-af2f-389b1d7c6e18" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_183a6c7a-7614-4d51-a57f-7ae9afd503b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_fbd5bd6f-3555-4df3-af2f-389b1d7c6e18" xlink:to="loc_us-gaap_StatementTable_183a6c7a-7614-4d51-a57f-7ae9afd503b2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_93cc0137-9b39-4c41-829e-995073e9883e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_183a6c7a-7614-4d51-a57f-7ae9afd503b2" xlink:to="loc_srt_ConsolidatedEntitiesAxis_93cc0137-9b39-4c41-829e-995073e9883e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_93cc0137-9b39-4c41-829e-995073e9883e_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_93cc0137-9b39-4c41-829e-995073e9883e" xlink:to="loc_srt_ConsolidatedEntitiesDomain_93cc0137-9b39-4c41-829e-995073e9883e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_fdd43319-02e8-4a3b-9f2b-3371e849e1b2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_93cc0137-9b39-4c41-829e-995073e9883e" xlink:to="loc_srt_ConsolidatedEntitiesDomain_fdd43319-02e8-4a3b-9f2b-3371e849e1b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_bef07e01-55bf-4d27-937e-bc93ad9fe2d3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_fdd43319-02e8-4a3b-9f2b-3371e849e1b2" xlink:to="loc_srt_PartnershipInterestMember_bef07e01-55bf-4d27-937e-bc93ad9fe2d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeAxis_d80d51a4-cc28-4f7b-850d-39261156f9a9" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_183a6c7a-7614-4d51-a57f-7ae9afd503b2" xlink:to="loc_frt_ConvertibleUnitTypeAxis_d80d51a4-cc28-4f7b-850d-39261156f9a9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_d80d51a4-cc28-4f7b-850d-39261156f9a9_default" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ConvertibleUnitTypeAxis_d80d51a4-cc28-4f7b-850d-39261156f9a9" xlink:to="loc_frt_ConvertibleUnitTypeDomain_d80d51a4-cc28-4f7b-850d-39261156f9a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_f41b9469-5ab5-4c75-b740-834823725cdd" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ConvertibleUnitTypeAxis_d80d51a4-cc28-4f7b-850d-39261156f9a9" xlink:to="loc_frt_ConvertibleUnitTypeDomain_f41b9469-5ab5-4c75-b740-834823725cdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DownREITOPUnitsMember_5a44af1d-0df9-4e01-9af8-177e8fcf91f5" xlink:href="frt-20240331.xsd#frt_DownREITOPUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ConvertibleUnitTypeDomain_f41b9469-5ab5-4c75-b740-834823725cdd" xlink:to="loc_frt_DownREITOPUnitsMember_5a44af1d-0df9-4e01-9af8-177e8fcf91f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_36cbbbea-5bb0-441b-888c-bb2f0f513add" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_183a6c7a-7614-4d51-a57f-7ae9afd503b2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_36cbbbea-5bb0-441b-888c-bb2f0f513add" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_36cbbbea-5bb0-441b-888c-bb2f0f513add_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_36cbbbea-5bb0-441b-888c-bb2f0f513add" xlink:to="loc_us-gaap_EquityComponentDomain_36cbbbea-5bb0-441b-888c-bb2f0f513add_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_36cbbbea-5bb0-441b-888c-bb2f0f513add" xlink:to="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredUnitsMember_779e6626-a378-4cec-a26c-45ce29b76a1f" xlink:href="frt-20240331.xsd#frt_PreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:to="loc_frt_PreferredUnitsMember_779e6626-a378-4cec-a26c-45ce29b76a1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonUnitsMember_fa5c58a3-dfc6-4fa5-b3c3-9ec8d474120c" xlink:href="frt-20240331.xsd#frt_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:to="loc_frt_CommonUnitsMember_fa5c58a3-dfc6-4fa5-b3c3-9ec8d474120c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_476cf584-3a75-49b4-a3c6-75e6daca0b69" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_476cf584-3a75-49b4-a3c6-75e6daca0b69" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_c0871145-1eb9-480a-8701-763ae8d00547" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:to="loc_us-gaap_ParentMember_c0871145-1eb9-480a-8701-763ae8d00547" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NoncontrollingInterestsInConsolidatedPartnershipsMember_9fee910d-147a-47e3-95f7-fe54f2578e34" xlink:href="frt-20240331.xsd#frt_NoncontrollingInterestsInConsolidatedPartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c147a8b5-7ea8-4163-96ca-a1ffa5489071" xlink:to="loc_frt_NoncontrollingInterestsInConsolidatedPartnershipsMember_9fee910d-147a-47e3-95f7-fe54f2578e34" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInPartnersCapitalRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_fbd5bd6f-3555-4df3-af2f-389b1d7c6e18" xlink:to="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_8d2ec362-f4a1-4f4b-9620-1e67688bc3f2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_8d2ec362-f4a1-4f4b-9620-1e67688bc3f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_deff0379-37a2-49f0-8b9f-1b768273f9d0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_deff0379-37a2-49f0-8b9f-1b768273f9d0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_9ed3c2cb-026e-4da7-90c2-cf0c11a9bedd" xlink:href="frt-20240331.xsd#frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_OtherComprehensiveIncomeLossNetOfPortionAttributableToNoncontrollingInterest_9ed3c2cb-026e-4da7-90c2-cf0c11a9bedd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DistributionsDeclaredToCommonUnitHolders_f2860494-9709-4ee7-ae73-f26d8ffafb68" xlink:href="frt-20240331.xsd#frt_DistributionsDeclaredToCommonUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_DistributionsDeclaredToCommonUnitHolders_f2860494-9709-4ee7-ae73-f26d8ffafb68" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DistributionsDeclaredToPreferredUnitHolders_c8439558-bb52-4af4-86b6-4a68f90b35c5" xlink:href="frt-20240331.xsd#frt_DistributionsDeclaredToPreferredUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_DistributionsDeclaredToPreferredUnitHolders_c8439558-bb52-4af4-86b6-4a68f90b35c5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DistributionsDeclaredToNoncontrollingInterestsInConsolidatedPartnershipsExcludingAmountsAttributableToRedeemableNoncontrollingInterests_43cfd1b5-0d8d-4009-b2ed-2a36504d705e" xlink:href="frt-20240331.xsd#frt_DistributionsDeclaredToNoncontrollingInterestsInConsolidatedPartnershipsExcludingAmountsAttributableToRedeemableNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_DistributionsDeclaredToNoncontrollingInterestsInConsolidatedPartnershipsExcludingAmountsAttributableToRedeemableNoncontrollingInterests_43cfd1b5-0d8d-4009-b2ed-2a36504d705e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountContributions_1f4001b1-ebc8-467b-8746-78f7bf75d25d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_us-gaap_PartnersCapitalAccountContributions_1f4001b1-ebc8-467b-8746-78f7bf75d25d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommonUnitsIssuedUnderDividendReinvestmentPlan_c3d5b214-f9b6-44a8-9e33-96580d27d57d" xlink:href="frt-20240331.xsd#frt_CommonUnitsIssuedUnderDividendReinvestmentPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_CommonUnitsIssuedUnderDividendReinvestmentPlan_c3d5b214-f9b6-44a8-9e33-96580d27d57d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_ebd5e9b9-4a30-4dd3-a910-011c4cb59dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountUnitBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_ebd5e9b9-4a30-4dd3-a910-011c4cb59dd8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PartnersCapitalAccountEmployeeTaxWithholdings_6c588dc5-2cbf-4739-9553-6c3d71b95f04" xlink:href="frt-20240331.xsd#frt_PartnersCapitalAccountEmployeeTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_PartnersCapitalAccountEmployeeTaxWithholdings_6c588dc5-2cbf-4739-9553-6c3d71b95f04" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountExchangesAndConversions_9d885b4d-4a07-4a80-bfae-6c3b0b96cff1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountExchangesAndConversions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_us-gaap_PartnersCapitalAccountExchangesAndConversions_9d885b4d-4a07-4a80-bfae-6c3b0b96cff1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Contributionsfromnoncontrollinginterests_2cca7964-4903-432e-ae57-d4b60f959586" xlink:href="frt-20240331.xsd#frt_Contributionsfromnoncontrollinginterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_Contributionsfromnoncontrollinginterests_2cca7964-4903-432e-ae57-d4b60f959586" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PartnersCapitalAccountCappedCallPremiums_d555d48e-7a9c-49fa-880d-31ab78e7272a" xlink:href="frt-20240331.xsd#frt_PartnersCapitalAccountCappedCallPremiums"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_0ec1c279-0ea0-4af4-9705-93865d3aaac2" xlink:to="loc_frt_PartnersCapitalAccountCappedCallPremiums_d555d48e-7a9c-49fa-880d-31ab78e7272a" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_9ae3be15-be0f-4a1a-b983-218e3490c7ac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ConsolidatedStatementsofCapitalParenthetical" xlink:type="simple" xlink:href="frt-20240331.xsd#ConsolidatedStatementsofCapitalParenthetical"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ConsolidatedStatementsofCapitalParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_23c28582-a61e-4479-a219-0f46827f9e40" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_460c6895-20ac-419c-96c5-5f9cd54cff0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_23c28582-a61e-4479-a219-0f46827f9e40" xlink:to="loc_us-gaap_StatementTable_460c6895-20ac-419c-96c5-5f9cd54cff0b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_d081fa3a-2d08-4912-9fa2-1c07ac0109b4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_460c6895-20ac-419c-96c5-5f9cd54cff0b" xlink:to="loc_srt_ConsolidatedEntitiesAxis_d081fa3a-2d08-4912-9fa2-1c07ac0109b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_d081fa3a-2d08-4912-9fa2-1c07ac0109b4_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_d081fa3a-2d08-4912-9fa2-1c07ac0109b4" xlink:to="loc_srt_ConsolidatedEntitiesDomain_d081fa3a-2d08-4912-9fa2-1c07ac0109b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_66c78346-f87d-426c-aad9-c825d1a104b9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_d081fa3a-2d08-4912-9fa2-1c07ac0109b4" xlink:to="loc_srt_ConsolidatedEntitiesDomain_66c78346-f87d-426c-aad9-c825d1a104b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_d7f0e561-d6ca-4523-9db1-a18c16d2ed0a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_66c78346-f87d-426c-aad9-c825d1a104b9" xlink:to="loc_srt_PartnershipInterestMember_d7f0e561-d6ca-4523-9db1-a18c16d2ed0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_9f32d10e-3ae5-4b85-b84c-5b47c67c235c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_23c28582-a61e-4479-a219-0f46827f9e40" xlink:to="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_9f32d10e-3ae5-4b85-b84c-5b47c67c235c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest_7b841efd-49d9-475d-8901-dfef839484b1" xlink:href="frt-20240331.xsd#frt_OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_23c28582-a61e-4479-a219-0f46827f9e40" xlink:to="loc_frt_OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest_7b841efd-49d9-475d-8901-dfef839484b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RedeemableNoncontrollingInterestDecreaseFromDistributionsToRedeemableNoncontrollingInterestHolders_42a2e269-0b2a-4a06-9b3c-60083f7c5026" xlink:href="frt-20240331.xsd#frt_RedeemableNoncontrollingInterestDecreaseFromDistributionsToRedeemableNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_23c28582-a61e-4479-a219-0f46827f9e40" xlink:to="loc_frt_RedeemableNoncontrollingInterestDecreaseFromDistributionsToRedeemableNoncontrollingInterestHolders_42a2e269-0b2a-4a06-9b3c-60083f7c5026" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/BusinessAndOrganizationDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#BusinessAndOrganizationDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/BusinessAndOrganizationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems_12f079d1-0b37-4308-b81b-ebe192c2e7e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_ec00109d-a6c4-4735-9bad-04248594ebd8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems_12f079d1-0b37-4308-b81b-ebe192c2e7e4" xlink:to="loc_us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_ec00109d-a6c4-4735-9bad-04248594ebd8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_288bbaba-9535-494f-aaff-6ad97f7ceba9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_ec00109d-a6c4-4735-9bad-04248594ebd8" xlink:to="loc_srt_OwnershipAxis_288bbaba-9535-494f-aaff-6ad97f7ceba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_288bbaba-9535-494f-aaff-6ad97f7ceba9_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_288bbaba-9535-494f-aaff-6ad97f7ceba9" xlink:to="loc_srt_OwnershipDomain_288bbaba-9535-494f-aaff-6ad97f7ceba9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_fb98bd4d-7952-4c83-a2d5-a909b3442dab" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_288bbaba-9535-494f-aaff-6ad97f7ceba9" xlink:to="loc_srt_OwnershipDomain_fb98bd4d-7952-4c83-a2d5-a909b3442dab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_FederalRealtyGPLLCMember_ebc37286-1b92-4f9f-8585-d21c5d15033e" xlink:href="frt-20240331.xsd#frt_FederalRealtyGPLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_fb98bd4d-7952-4c83-a2d5-a909b3442dab" xlink:to="loc_frt_FederalRealtyGPLLCMember_ebc37286-1b92-4f9f-8585-d21c5d15033e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_7d93b7cf-e174-4a6b-890a-c872c89591fc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems_12f079d1-0b37-4308-b81b-ebe192c2e7e4" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_7d93b7cf-e174-4a6b-890a-c872c89591fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_7d276f38-f801-40e8-944b-2e9e6ef0ade1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems_12f079d1-0b37-4308-b81b-ebe192c2e7e4" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_7d276f38-f801-40e8-944b-2e9e6ef0ade1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MinimumPercentageOfTaxableIncomeDistributedToShareholders_b9e3d3c4-e387-44a2-b2a3-c6e1eb3674f3" xlink:href="frt-20240331.xsd#frt_MinimumPercentageOfTaxableIncomeDistributedToShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems_12f079d1-0b37-4308-b81b-ebe192c2e7e4" xlink:to="loc_frt_MinimumPercentageOfTaxableIncomeDistributedToShareholders_b9e3d3c4-e387-44a2-b2a3-c6e1eb3674f3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesExchangeableSeniorNotesDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#SummaryOfSignificantAccountingPoliciesExchangeableSeniorNotesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SummaryOfSignificantAccountingPoliciesExchangeableSeniorNotesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_frt_ExchangeableSeniorNotesLineItems_54f8fafc-5181-4f6f-b56d-fcb8b872ca4a" xlink:href="frt-20240331.xsd#frt_ExchangeableSeniorNotesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ExchangeableSeniorNotesTable_97314838-bfbf-4e12-a372-18f487d6ade8" xlink:href="frt-20240331.xsd#frt_ExchangeableSeniorNotesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_frt_ExchangeableSeniorNotesLineItems_54f8fafc-5181-4f6f-b56d-fcb8b872ca4a" xlink:to="loc_frt_ExchangeableSeniorNotesTable_97314838-bfbf-4e12-a372-18f487d6ade8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6b62d169-b591-4c59-8cb4-a482a053b255" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frt_ExchangeableSeniorNotesTable_97314838-bfbf-4e12-a372-18f487d6ade8" xlink:to="loc_us-gaap_DebtInstrumentAxis_6b62d169-b591-4c59-8cb4-a482a053b255" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6b62d169-b591-4c59-8cb4-a482a053b255_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6b62d169-b591-4c59-8cb4-a482a053b255" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6b62d169-b591-4c59-8cb4-a482a053b255_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01b48b25-bd10-4693-b6a9-a0b880fa2dc7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6b62d169-b591-4c59-8cb4-a482a053b255" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01b48b25-bd10-4693-b6a9-a0b880fa2dc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior3Point25PercentNotesMember_72c72aed-1438-4f1e-a658-e8057df86765" xlink:href="frt-20240331.xsd#frt_Senior3Point25PercentNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01b48b25-bd10-4693-b6a9-a0b880fa2dc7" xlink:to="loc_frt_Senior3Point25PercentNotesMember_72c72aed-1438-4f1e-a658-e8057df86765" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_6fe9bafb-f777-4184-858d-8fd4f3032dac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frt_ExchangeableSeniorNotesTable_97314838-bfbf-4e12-a372-18f487d6ade8" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_6fe9bafb-f777-4184-858d-8fd4f3032dac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6fe9bafb-f777-4184-858d-8fd4f3032dac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6fe9bafb-f777-4184-858d-8fd4f3032dac" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6fe9bafb-f777-4184-858d-8fd4f3032dac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_00b15a07-84b1-4ed6-93b7-4d11f7991e1f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6fe9bafb-f777-4184-858d-8fd4f3032dac" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_00b15a07-84b1-4ed6-93b7-4d11f7991e1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_fc961087-e794-47b1-8d78-3dbd808cfdab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_00b15a07-84b1-4ed6-93b7-4d11f7991e1f" xlink:to="loc_us-gaap_ConvertibleDebtMember_fc961087-e794-47b1-8d78-3dbd808cfdab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_d0dab121-b01c-4232-a8dc-dbb5fbbbd357" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ExchangeableSeniorNotesLineItems_54f8fafc-5181-4f6f-b56d-fcb8b872ca4a" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_d0dab121-b01c-4232-a8dc-dbb5fbbbd357" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_39507b06-c53d-4f9c-b4bd-a35afcebd43c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ExchangeableSeniorNotesLineItems_54f8fafc-5181-4f6f-b56d-fcb8b872ca4a" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_39507b06-c53d-4f9c-b4bd-a35afcebd43c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/DebtDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#DebtDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/DebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_73df5d2e-e42e-4251-9d63-7b9d27162971" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:to="loc_us-gaap_DebtInstrumentAxis_73df5d2e-e42e-4251-9d63-7b9d27162971" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_73df5d2e-e42e-4251-9d63-7b9d27162971_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_73df5d2e-e42e-4251-9d63-7b9d27162971" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_73df5d2e-e42e-4251-9d63-7b9d27162971_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_709121e3-be56-439c-ab5e-278538003639" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_73df5d2e-e42e-4251-9d63-7b9d27162971" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_709121e3-be56-439c-ab5e-278538003639" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior3Point25PercentNotesMember_b5b21388-ac84-4e33-b98e-4591244c1473" xlink:href="frt-20240331.xsd#frt_Senior3Point25PercentNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_709121e3-be56-439c-ab5e-278538003639" xlink:to="loc_frt_Senior3Point25PercentNotesMember_b5b21388-ac84-4e33-b98e-4591244c1473" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior3Point95PercentNotesMember_c6e7e86d-8ae6-4bec-8e8d-4d07f633b968" xlink:href="frt-20240331.xsd#frt_Senior3Point95PercentNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_709121e3-be56-439c-ab5e-278538003639" xlink:to="loc_frt_Senior3Point95PercentNotesMember_c6e7e86d-8ae6-4bec-8e8d-4d07f633b968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_c24ee085-ab39-49e9-b0b1-a1160c5e4ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_709121e3-be56-439c-ab5e-278538003639" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_c24ee085-ab39-49e9-b0b1-a1160c5e4ab3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_71e3c98c-9da7-4ea5-8de1-ef8cbf5dcb53" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8f229249-1e4c-4e31-8cc0-8a3ef03c05fc" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_71e3c98c-9da7-4ea5-8de1-ef8cbf5dcb53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5694d501-b10f-4276-adc0-0499ead82c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_87c49a13-4b78-4d9e-aaff-ccdd4f13ff08" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5694d501-b10f-4276-adc0-0499ead82c8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_abd07308-92df-4a59-8817-308363a0721c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5694d501-b10f-4276-adc0-0499ead82c8c" xlink:to="loc_us-gaap_ConvertibleDebtMember_abd07308-92df-4a59-8817-308363a0721c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_8c6f26da-6450-4045-9882-5a5aa9971783" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5694d501-b10f-4276-adc0-0499ead82c8c" xlink:to="loc_us-gaap_SeniorNotesMember_8c6f26da-6450-4045-9882-5a5aa9971783" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_TermloanMember_e644d99a-0664-4a8e-a8f8-a39c52b19f9e" xlink:href="frt-20240331.xsd#frt_TermloanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5694d501-b10f-4276-adc0-0499ead82c8c" xlink:to="loc_frt_TermloanMember_e644d99a-0664-4a8e-a8f8-a39c52b19f9e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OptionIndexedToIssuersEquityTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_f096990d-c4a7-4d3d-a1b8-fb6cff089d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_65f68ec8-25d7-47c1-a2f9-e6abb4f93a55" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_f096990d-c4a7-4d3d-a1b8-fb6cff089d3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CallOptionMember_3aab6c9a-7402-4e10-9a1b-4c3fbfba962a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CallOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_f096990d-c4a7-4d3d-a1b8-fb6cff089d3e" xlink:to="loc_us-gaap_CallOptionMember_3aab6c9a-7402-4e10-9a1b-4c3fbfba962a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_6a162cfb-b30b-48d6-967d-705888b8a9c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtConversionByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1e4b9b6f-1352-4578-b197-83a6b2a3e5f9" xlink:to="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_6a162cfb-b30b-48d6-967d-705888b8a9c1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionNameDomain_6a162cfb-b30b-48d6-967d-705888b8a9c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtConversionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_6a162cfb-b30b-48d6-967d-705888b8a9c1" xlink:to="loc_us-gaap_DebtConversionNameDomain_6a162cfb-b30b-48d6-967d-705888b8a9c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionNameDomain_647b267c-a5d6-4894-a48d-c76e1adb0e43" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtConversionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_6a162cfb-b30b-48d6-967d-705888b8a9c1" xlink:to="loc_us-gaap_DebtConversionNameDomain_647b267c-a5d6-4894-a48d-c76e1adb0e43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Per1000PrincipalAmountMember_2a36902f-2289-4940-940b-cb565336f3ae" xlink:href="frt-20240331.xsd#frt_Per1000PrincipalAmountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_647b267c-a5d6-4894-a48d-c76e1adb0e43" xlink:to="loc_frt_Per1000PrincipalAmountMember_2a36902f-2289-4940-940b-cb565336f3ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_daf36dbb-a5e7-4ed0-ad05-ec9be464d0f0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_daf36dbb-a5e7-4ed0-ad05-ec9be464d0f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_f57bf7e7-e882-4186-aab4-b0351e4c9fc1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_f57bf7e7-e882-4186-aab4-b0351e4c9fc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_e21b821b-b087-4f5c-84bd-6cea83f90e18" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_e21b821b-b087-4f5c-84bd-6cea83f90e18" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_aadeecd1-92a7-44f6-b529-37176561f257" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_InterestExpenseDebt_aadeecd1-92a7-44f6-b529-37176561f257" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_401a74d2-86e2-4cac-931d-4250aac46bc5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_401a74d2-86e2-4cac-931d-4250aac46bc5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_8a8791c1-c99e-4b9a-b893-d05a1944a124" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_8a8791c1-c99e-4b9a-b893-d05a1944a124" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_a3b4e53a-bb94-45ce-abe8-f9a5ac58eb6a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_a3b4e53a-bb94-45ce-abe8-f9a5ac58eb6a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ExchangePremiumPercentage_1093b7e7-6361-459e-9061-6f60effb8b38" xlink:href="frt-20240331.xsd#frt_ExchangePremiumPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_ExchangePremiumPercentage_1093b7e7-6361-459e-9061-6f60effb8b38" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharePrice_4c3cda1e-0244-4d76-8220-d0633613abc7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_SharePrice_4c3cda1e-0244-4d76-8220-d0633613abc7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_ef2b72ea-227e-4397-b88f-d1f826952f17" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_ef2b72ea-227e-4397-b88f-d1f826952f17" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MinimumRedemptionExchangePrice_8ed54a03-7dc6-4845-b21a-9a92f8b43e1e" xlink:href="frt-20240331.xsd#frt_MinimumRedemptionExchangePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_MinimumRedemptionExchangePrice_8ed54a03-7dc6-4845-b21a-9a92f8b43e1e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_6b11bb13-e444-4e01-ab83-bacc0e568806" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_6b11bb13-e444-4e01-ab83-bacc0e568806" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CappedCallCapSharePrice_9dbb8b91-783d-4287-a011-5ccb42e4d860" xlink:href="frt-20240331.xsd#frt_CappedCallCapSharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_CappedCallCapSharePrice_9dbb8b91-783d-4287-a011-5ccb42e4d860" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CappedCallPremiumPercentage_5b02b2a7-3d68-460e-8f60-41cb750fe7aa" xlink:href="frt-20240331.xsd#frt_CappedCallPremiumPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_CappedCallPremiumPercentage_5b02b2a7-3d68-460e-8f60-41cb750fe7aa" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CappedCallPremium_d010fd37-bddf-4fa2-a4cb-8af2de3f4bd0" xlink:href="frt-20240331.xsd#frt_CappedCallPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_CappedCallPremium_d010fd37-bddf-4fa2-a4cb-8af2de3f4bd0" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfUnsecuredDebt_5b38eac2-46d6-4783-95be-d8302affe6bf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RepaymentsOfUnsecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_RepaymentsOfUnsecuredDebt_5b38eac2-46d6-4783-95be-d8302affe6bf" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNotesPayable_660edeb5-c361-4e92-97d9-fe3d4e4596fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_OtherNotesPayable_660edeb5-c361-4e92-97d9-fe3d4e4596fa" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_cdc2f25b-e6ad-4008-ab56-cad70d9690fd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_cdc2f25b-e6ad-4008-ab56-cad70d9690fd" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod_14a91c86-ac3b-4f06-99d7-52d43d7be01a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod_14a91c86-ac3b-4f06-99d7-52d43d7be01a" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAverageOutstandingAmount_64bb3257-e522-47f3-b6fa-bfb60b68bf4d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_LineOfCreditFacilityAverageOutstandingAmount_64bb3257-e522-47f3-b6fa-bfb60b68bf4d" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees_8afc635a-8e41-4e26-b167-22f2aa621931" xlink:href="frt-20240331.xsd#frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_frt_LineofcreditfacilityweightedaverageinterestratebeforeamortizationofdebtFees_8afc635a-8e41-4e26-b167-22f2aa621931" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_e92de89b-4ebd-4934-80ad-5c83a873a18c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8311a9ed-a1f1-4cd4-880e-a10ea491afbf" xlink:to="loc_us-gaap_LineOfCredit_e92de89b-4ebd-4934-80ad-5c83a873a18c" xlink:type="arc" order="21"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueofFinancialInstrumentsSummaryofCarryingValueandFairValueofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#FairValueofFinancialInstrumentsSummaryofCarryingValueandFairValueofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueofFinancialInstrumentsSummaryofCarryingValueandFairValueofFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_128f858f-5da5-4e02-a512-1cf7b700c96d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_de519a79-3654-4660-b679-9747591a87d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_128f858f-5da5-4e02-a512-1cf7b700c96d" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_de519a79-3654-4660-b679-9747591a87d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_1e23b976-164c-46ef-bbce-a6d7d6ec5e35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_de519a79-3654-4660-b679-9747591a87d1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_1e23b976-164c-46ef-bbce-a6d7d6ec5e35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1e23b976-164c-46ef-bbce-a6d7d6ec5e35_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1e23b976-164c-46ef-bbce-a6d7d6ec5e35" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1e23b976-164c-46ef-bbce-a6d7d6ec5e35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_853ca150-3c5c-48ab-9db1-320921cb556d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1e23b976-164c-46ef-bbce-a6d7d6ec5e35" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_853ca150-3c5c-48ab-9db1-320921cb556d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_MortgagesPayableAndNotesPayableMember_c5cfc93a-d06c-4627-afa4-64e32895a6a8" xlink:href="frt-20240331.xsd#frt_MortgagesPayableAndNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_853ca150-3c5c-48ab-9db1-320921cb556d" xlink:to="loc_frt_MortgagesPayableAndNotesPayableMember_c5cfc93a-d06c-4627-afa4-64e32895a6a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_SeniorNotesAndDebenturesMember_c146cc3d-7f99-4b1d-a431-c7f4ae902374" xlink:href="frt-20240331.xsd#frt_SeniorNotesAndDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_853ca150-3c5c-48ab-9db1-320921cb556d" xlink:to="loc_frt_SeniorNotesAndDebenturesMember_c146cc3d-7f99-4b1d-a431-c7f4ae902374" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_09294c44-693a-4de1-88e8-749984179ca3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_de519a79-3654-4660-b679-9747591a87d1" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_09294c44-693a-4de1-88e8-749984179ca3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_09294c44-693a-4de1-88e8-749984179ca3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_09294c44-693a-4de1-88e8-749984179ca3" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_09294c44-693a-4de1-88e8-749984179ca3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_835be198-e3fb-4582-9a87-60cb7c71a78a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_09294c44-693a-4de1-88e8-749984179ca3" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_835be198-e3fb-4582-9a87-60cb7c71a78a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ac485013-f050-4d0b-90e6-5024eae21cc9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_835be198-e3fb-4582-9a87-60cb7c71a78a" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ac485013-f050-4d0b-90e6-5024eae21cc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_ae9f75b8-6ffd-416e-82ca-02b00efdfe4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ac485013-f050-4d0b-90e6-5024eae21cc9" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_ae9f75b8-6ffd-416e-82ca-02b00efdfe4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_18e526f8-e10a-4948-9069-aa9af30491e2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ac485013-f050-4d0b-90e6-5024eae21cc9" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_18e526f8-e10a-4948-9069-aa9af30491e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_c09cfa17-0f16-4e45-b650-6ae5c1980b82" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_128f858f-5da5-4e02-a512-1cf7b700c96d" xlink:to="loc_us-gaap_LongTermDebtFairValue_c09cfa17-0f16-4e45-b650-6ae5c1980b82" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#FairValueOfFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueOfFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_86fab1db-ded8-4bb2-9307-1be174507081" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_DebtInstrumentAxis_86fab1db-ded8-4bb2-9307-1be174507081" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_86fab1db-ded8-4bb2-9307-1be174507081_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_86fab1db-ded8-4bb2-9307-1be174507081" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_86fab1db-ded8-4bb2-9307-1be174507081_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_578a0d58-f69b-45bc-9af7-223c145c41ce" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_86fab1db-ded8-4bb2-9307-1be174507081" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_578a0d58-f69b-45bc-9af7-223c145c41ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_HobokenMember_29dc3342-7401-4a28-812d-afc8e8898535" xlink:href="frt-20240331.xsd#frt_HobokenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_578a0d58-f69b-45bc-9af7-223c145c41ce" xlink:to="loc_frt_HobokenMember_29dc3342-7401-4a28-812d-afc8e8898535" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_BethesdaRowMember_098d553f-0946-46f2-8dd9-62b65f255ebf" xlink:href="frt-20240331.xsd#frt_BethesdaRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_578a0d58-f69b-45bc-9af7-223c145c41ce" xlink:to="loc_frt_BethesdaRowMember_098d553f-0946-46f2-8dd9-62b65f255ebf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_9103df79-fdc9-4dc9-8b32-6810231ca219" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_9103df79-fdc9-4dc9-8b32-6810231ca219" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_9103df79-fdc9-4dc9-8b32-6810231ca219_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9103df79-fdc9-4dc9-8b32-6810231ca219" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_9103df79-fdc9-4dc9-8b32-6810231ca219_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_dcd346bd-d11e-4775-8713-63ffb70c7ad2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9103df79-fdc9-4dc9-8b32-6810231ca219" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_dcd346bd-d11e-4775-8713-63ffb70c7ad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_d3f37e6a-870d-4227-8808-68231f37d5bb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_dcd346bd-d11e-4775-8713-63ffb70c7ad2" xlink:to="loc_us-gaap_SecuredDebtMember_d3f37e6a-870d-4227-8808-68231f37d5bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f540419a-6c54-428c-9f46-c97c07059104" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f540419a-6c54-428c-9f46-c97c07059104" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_f540419a-6c54-428c-9f46-c97c07059104_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f540419a-6c54-428c-9f46-c97c07059104" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_f540419a-6c54-428c-9f46-c97c07059104_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_263889b1-455e-47c1-96b1-48a34269219c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f540419a-6c54-428c-9f46-c97c07059104" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_263889b1-455e-47c1-96b1-48a34269219c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_93afa69f-41ff-4fda-90a3-1c007716162a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_263889b1-455e-47c1-96b1-48a34269219c" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_93afa69f-41ff-4fda-90a3-1c007716162a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3f130d36-2b61-4682-896e-a6dbcbe6c1a4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3f130d36-2b61-4682-896e-a6dbcbe6c1a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3f130d36-2b61-4682-896e-a6dbcbe6c1a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3f130d36-2b61-4682-896e-a6dbcbe6c1a4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3f130d36-2b61-4682-896e-a6dbcbe6c1a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_6452fa40-77c0-425c-9965-a548676f55e0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3f130d36-2b61-4682-896e-a6dbcbe6c1a4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_6452fa40-77c0-425c-9965-a548676f55e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_e0b74a97-f44b-44d0-8d8c-d3cc1adc7054" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6452fa40-77c0-425c-9965-a548676f55e0" xlink:to="loc_us-gaap_InterestRateSwapMember_e0b74a97-f44b-44d0-8d8c-d3cc1adc7054" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_b465d2c5-8403-425d-b09c-166c9ed64d62" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_b465d2c5-8403-425d-b09c-166c9ed64d62" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b465d2c5-8403-425d-b09c-166c9ed64d62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b465d2c5-8403-425d-b09c-166c9ed64d62" xlink:to="loc_us-gaap_EquityComponentDomain_b465d2c5-8403-425d-b09c-166c9ed64d62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_298a263c-e76e-438e-96d8-f8fee9122172" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b465d2c5-8403-425d-b09c-166c9ed64d62" xlink:to="loc_us-gaap_EquityComponentDomain_298a263c-e76e-438e-96d8-f8fee9122172" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_c9dae7f6-fb92-4ca1-94fc-05b4d910ce7f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_298a263c-e76e-438e-96d8-f8fee9122172" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_c9dae7f6-fb92-4ca1-94fc-05b4d910ce7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_65a2379e-0ba4-4993-8e82-d3efdcfc1649" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_838b27ea-1c5b-40a7-887b-e84adc8c05d1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_65a2379e-0ba4-4993-8e82-d3efdcfc1649" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_65a2379e-0ba4-4993-8e82-d3efdcfc1649_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_65a2379e-0ba4-4993-8e82-d3efdcfc1649" xlink:to="loc_us-gaap_RelatedPartyDomain_65a2379e-0ba4-4993-8e82-d3efdcfc1649_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_f98a31d4-b601-4911-82b6-0df008974832" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_65a2379e-0ba4-4993-8e82-d3efdcfc1649" xlink:to="loc_us-gaap_RelatedPartyDomain_f98a31d4-b601-4911-82b6-0df008974832" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_78fdcb12-db4e-4226-85c8-aa8409360ec2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_f98a31d4-b601-4911-82b6-0df008974832" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_78fdcb12-db4e-4226-85c8-aa8409360ec2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfInterestRateDerivativesHeld_c8d4d112-7559-4d25-81c5-d736398c2938" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfInterestRateDerivativesHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_NumberOfInterestRateDerivativesHeld_c8d4d112-7559-4d25-81c5-d736398c2938" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_da828f03-d241-4a3c-8a08-d93028e84ac2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_DerivativeNotionalAmount_da828f03-d241-4a3c-8a08-d93028e84ac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_8df29bf3-3036-414f-aaf1-2fa8267cdeb4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_8df29bf3-3036-414f-aaf1-2fa8267cdeb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_5b43e68c-ecc1-4e72-b512-33d929187f73" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_5b43e68c-ecc1-4e72-b512-33d929187f73" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_dc025d5f-aa5d-4bdf-84bb-96ed25ee94e0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_dc025d5f-aa5d-4bdf-84bb-96ed25ee94e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_1a1df463-6a0b-4cc5-8172-a27da04137d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_1a1df463-6a0b-4cc5-8172-a27da04137d2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_94d83b9e-c4a4-4758-8f9d-2bce69931e5a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7e184390-dffa-4f34-b7e0-bd296c80cfa2" xlink:to="loc_us-gaap_DerivativeAssets_94d83b9e-c4a4-4758-8f9d-2bce69931e5a" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/FairValueofFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#FairValueofFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/FairValueofFinancialInstrumentsSummaryofFinancialLiabilitiesMeasuredAtFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_bb2b905d-6a6a-4e18-b190-f63c93a5a0cc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_e16611ee-068a-469f-8a4c-2dfbdd538b28" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_bb2b905d-6a6a-4e18-b190-f63c93a5a0cc" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_e16611ee-068a-469f-8a4c-2dfbdd538b28" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_5bbdff48-dea3-490c-a844-a25d2afd44f7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_e16611ee-068a-469f-8a4c-2dfbdd538b28" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_5bbdff48-dea3-490c-a844-a25d2afd44f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5bbdff48-dea3-490c-a844-a25d2afd44f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_5bbdff48-dea3-490c-a844-a25d2afd44f7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5bbdff48-dea3-490c-a844-a25d2afd44f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_9945d3cc-2449-42eb-89ce-a44f86ddfc4f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_5bbdff48-dea3-490c-a844-a25d2afd44f7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_9945d3cc-2449-42eb-89ce-a44f86ddfc4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_f8355552-ef04-4b53-9de4-818efdb7189b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_9945d3cc-2449-42eb-89ce-a44f86ddfc4f" xlink:to="loc_us-gaap_InterestRateSwapMember_f8355552-ef04-4b53-9de4-818efdb7189b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_577f00b9-05af-4738-bb09-b4976c788bff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_e16611ee-068a-469f-8a4c-2dfbdd538b28" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_577f00b9-05af-4738-bb09-b4976c788bff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_577f00b9-05af-4738-bb09-b4976c788bff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_577f00b9-05af-4738-bb09-b4976c788bff" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_577f00b9-05af-4738-bb09-b4976c788bff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_12ba2215-3963-44ab-965f-25b13c7c7df1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_577f00b9-05af-4738-bb09-b4976c788bff" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_12ba2215-3963-44ab-965f-25b13c7c7df1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_68bcb247-8274-438f-ad3d-a2e65df5082c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_12ba2215-3963-44ab-965f-25b13c7c7df1" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_68bcb247-8274-438f-ad3d-a2e65df5082c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_093ec952-4925-4f0f-9b7c-cf56f7281b28" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_12ba2215-3963-44ab-965f-25b13c7c7df1" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_093ec952-4925-4f0f-9b7c-cf56f7281b28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_407e80d8-7201-4367-b155-cf772c4500d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_12ba2215-3963-44ab-965f-25b13c7c7df1" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_407e80d8-7201-4367-b155-cf772c4500d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_cccb4c0f-e92d-4382-a4ff-409483d8f94b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_e16611ee-068a-469f-8a4c-2dfbdd538b28" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_cccb4c0f-e92d-4382-a4ff-409483d8f94b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_cccb4c0f-e92d-4382-a4ff-409483d8f94b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_cccb4c0f-e92d-4382-a4ff-409483d8f94b" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_cccb4c0f-e92d-4382-a4ff-409483d8f94b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_8b068102-47f4-450f-b1b7-dfb451562d66" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_cccb4c0f-e92d-4382-a4ff-409483d8f94b" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_8b068102-47f4-450f-b1b7-dfb451562d66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_e0a24c81-f78e-4b91-ada3-b818d48d596a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_8b068102-47f4-450f-b1b7-dfb451562d66" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_e0a24c81-f78e-4b91-ada3-b818d48d596a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_e00ba20d-e2a5-41c2-9637-7a3bfb53b5a4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_bb2b905d-6a6a-4e18-b190-f63c93a5a0cc" xlink:to="loc_us-gaap_DerivativeAssets_e00ba20d-e2a5-41c2-9637-7a3bfb53b5a4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#CommitmentsandContingenciesDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/CommitmentsandContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_8449fd4b-3e6c-4229-a4b7-7a1c1cc6d304" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_551a7ed1-dcd2-40b2-adbc-f803cb5d0f73" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_8449fd4b-3e6c-4229-a4b7-7a1c1cc6d304" xlink:to="loc_us-gaap_OtherCommitmentsTable_551a7ed1-dcd2-40b2-adbc-f803cb5d0f73" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeAxis_1efa6096-f8aa-4e11-9395-f05d1005f7db" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_551a7ed1-dcd2-40b2-adbc-f803cb5d0f73" xlink:to="loc_frt_ConvertibleUnitTypeAxis_1efa6096-f8aa-4e11-9395-f05d1005f7db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_1efa6096-f8aa-4e11-9395-f05d1005f7db_default" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ConvertibleUnitTypeAxis_1efa6096-f8aa-4e11-9395-f05d1005f7db" xlink:to="loc_frt_ConvertibleUnitTypeDomain_1efa6096-f8aa-4e11-9395-f05d1005f7db_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ConvertibleUnitTypeDomain_f4835f44-933b-4698-b1e4-9c6514493125" xlink:href="frt-20240331.xsd#frt_ConvertibleUnitTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ConvertibleUnitTypeAxis_1efa6096-f8aa-4e11-9395-f05d1005f7db" xlink:to="loc_frt_ConvertibleUnitTypeDomain_f4835f44-933b-4698-b1e4-9c6514493125" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DownREITOPUnitsMember_ca247e4c-3057-4920-94ae-172e2d5597b9" xlink:href="frt-20240331.xsd#frt_DownREITOPUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ConvertibleUnitTypeDomain_f4835f44-933b-4698-b1e4-9c6514493125" xlink:to="loc_frt_DownREITOPUnitsMember_ca247e4c-3057-4920-94ae-172e2d5597b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnits_63dbcfa5-97c9-412e-845c-b9dc62fc3fff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_8449fd4b-3e6c-4229-a4b7-7a1c1cc6d304" xlink:to="loc_us-gaap_PartnersCapitalAccountUnits_63dbcfa5-97c9-412e-845c-b9dc62fc3fff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OperatingPartnershipUnitsFairValue_99505447-fc72-456b-8fab-42241a095d4e" xlink:href="frt-20240331.xsd#frt_OperatingPartnershipUnitsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_8449fd4b-3e6c-4229-a4b7-7a1c1cc6d304" xlink:to="loc_frt_OperatingPartnershipUnitsFairValue_99505447-fc72-456b-8fab-42241a095d4e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareholdersEquitySummaryofDividendsDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#ShareholdersEquitySummaryofDividendsDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareholdersEquitySummaryofDividendsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableTable_f74017d2-1acb-414f-92cd-9c099a4c88c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_DividendsPayableTable_f74017d2-1acb-414f-92cd-9c099a4c88c3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DividendsPayableTable_f74017d2-1acb-414f-92cd-9c099a4c88c3" xlink:to="loc_us-gaap_StatementClassOfStockAxis_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2" xlink:to="loc_us-gaap_ClassOfStockDomain_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_30acb7f5-3267-4f5b-bef6-8acec0bb02c7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_fe8fcdd8-dea9-4e0f-9bf2-696096ed2ac2" xlink:to="loc_us-gaap_ClassOfStockDomain_30acb7f5-3267-4f5b-bef6-8acec0bb02c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_920bbd73-c503-4db3-a1fa-4b15da8177cf" xlink:href="frt-20240331.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_30acb7f5-3267-4f5b-bef6-8acec0bb02c7" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_920bbd73-c503-4db3-a1fa-4b15da8177cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_75d9a2aa-2242-4e9a-8e8a-5063fe99f882" xlink:href="frt-20240331.xsd#frt_A5.0SeriesCCumulativeRedeemablePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_30acb7f5-3267-4f5b-bef6-8acec0bb02c7" xlink:to="loc_frt_A5.0SeriesCCumulativeRedeemablePreferredMember_75d9a2aa-2242-4e9a-8e8a-5063fe99f882" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_10c61893-36f9-4359-a92a-32b2b366f7db" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_10c61893-36f9-4359-a92a-32b2b366f7db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_d183a546-99e4-45f4-acb2-882b8a924545" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_d183a546-99e4-45f4-acb2-882b8a924545" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_f87ccfef-feac-411e-8d6c-9ac95cd5a65d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_f87ccfef-feac-411e-8d6c-9ac95cd5a65d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareDeclared_ecc4d397-7c65-409d-964b-15fab0587af3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_PreferredStockDividendsPerShareDeclared_ecc4d397-7c65-409d-964b-15fab0587af3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_6db64b30-4de3-449e-a6b0-9bcb4f7f12ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_8c787582-5bbe-4c6a-8848-8e2e8c35ff7a" xlink:to="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_6db64b30-4de3-449e-a6b0-9bcb4f7f12ae" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/ShareholdersEquityNarrativeDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#ShareholdersEquityNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/ShareholdersEquityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_8ae07ac2-34bf-42f1-ab8c-970fb9c92c31" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_8ae07ac2-34bf-42f1-ab8c-970fb9c92c31" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_38afa3ab-addc-41c3-9fac-ee5ce08332e6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_8ae07ac2-34bf-42f1-ab8c-970fb9c92c31" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_38afa3ab-addc-41c3-9fac-ee5ce08332e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_38afa3ab-addc-41c3-9fac-ee5ce08332e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_38afa3ab-addc-41c3-9fac-ee5ce08332e6" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_38afa3ab-addc-41c3-9fac-ee5ce08332e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_e16ccb7b-3316-4a75-87f6-f3f296986459" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_38afa3ab-addc-41c3-9fac-ee5ce08332e6" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_e16ccb7b-3316-4a75-87f6-f3f296986459" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AtMarketEquityProgramMember_07aaea4a-9968-4b69-994d-9b2e6d8248ef" xlink:href="frt-20240331.xsd#frt_AtMarketEquityProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_e16ccb7b-3316-4a75-87f6-f3f296986459" xlink:to="loc_frt_AtMarketEquityProgramMember_07aaea4a-9968-4b69-994d-9b2e6d8248ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeAxis_8741416e-9fcc-45de-a5c8-178c06055f91" xlink:href="frt-20240331.xsd#frt_StockIssuanceCostsByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_8ae07ac2-34bf-42f1-ab8c-970fb9c92c31" xlink:to="loc_frt_StockIssuanceCostsByTypeAxis_8741416e-9fcc-45de-a5c8-178c06055f91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeDomain_8741416e-9fcc-45de-a5c8-178c06055f91_default" xlink:href="frt-20240331.xsd#frt_StockIssuanceCostsByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_StockIssuanceCostsByTypeAxis_8741416e-9fcc-45de-a5c8-178c06055f91" xlink:to="loc_frt_StockIssuanceCostsByTypeDomain_8741416e-9fcc-45de-a5c8-178c06055f91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockIssuanceCostsByTypeDomain_d776d939-dc65-4912-a71e-a0a71c79577b" xlink:href="frt-20240331.xsd#frt_StockIssuanceCostsByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_StockIssuanceCostsByTypeAxis_8741416e-9fcc-45de-a5c8-178c06055f91" xlink:to="loc_frt_StockIssuanceCostsByTypeDomain_d776d939-dc65-4912-a71e-a0a71c79577b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CommissionsMember_eb11ab51-6df1-44a9-8582-583b2f218a35" xlink:href="frt-20240331.xsd#frt_CommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_StockIssuanceCostsByTypeDomain_d776d939-dc65-4912-a71e-a0a71c79577b" xlink:to="loc_frt_CommissionsMember_eb11ab51-6df1-44a9-8582-583b2f218a35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OtherOfferingCostsMember_9ae23ae4-8a74-41ef-aee7-e31992b0efec" xlink:href="frt-20240331.xsd#frt_OtherOfferingCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_StockIssuanceCostsByTypeDomain_d776d939-dc65-4912-a71e-a0a71c79577b" xlink:to="loc_frt_OtherOfferingCostsMember_9ae23ae4-8a74-41ef-aee7-e31992b0efec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AggregateOfferingPriceOfCommonShare_108baafe-f33b-4a5a-8a7f-4472be29bb95" xlink:href="frt-20240331.xsd#frt_AggregateOfferingPriceOfCommonShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_frt_AggregateOfferingPriceOfCommonShare_108baafe-f33b-4a5a-8a7f-4472be29bb95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_a976d9ec-92d7-4833-a55e-c1c92b5b181c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_a976d9ec-92d7-4833-a55e-c1c92b5b181c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WeightedAveragePricePerCommonShare_9c8dab16-adbd-48ab-96fd-836941bc65f3" xlink:href="frt-20240331.xsd#frt_WeightedAveragePricePerCommonShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_frt_WeightedAveragePricePerCommonShare_9c8dab16-adbd-48ab-96fd-836941bc65f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_cd58b067-fcc1-4f64-90ad-f652c7167892" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_cd58b067-fcc1-4f64-90ad-f652c7167892" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_c775b2f1-d8f8-4577-ac4a-9961319690ee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_c775b2f1-d8f8-4577-ac4a-9961319690ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_RemainingCapacityToIssue_b7e54dac-dfd5-4947-9ecf-9fdb074618ff" xlink:href="frt-20240331.xsd#frt_RemainingCapacityToIssue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_8fe68763-07c0-439e-8d5a-f15e4556e91c" xlink:to="loc_frt_RemainingCapacityToIssue_b7e54dac-dfd5-4947-9ecf-9fdb074618ff" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/EarningsPerShareAndUnitDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#EarningsPerShareAndUnitDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/EarningsPerShareAndUnitDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeAxis_2a8ac5bd-2fdb-4651-9322-903519557850" xlink:href="frt-20240331.xsd#frt_ShareTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_frt_ShareTypeAxis_2a8ac5bd-2fdb-4651-9322-903519557850" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeDomain_2a8ac5bd-2fdb-4651-9322-903519557850_default" xlink:href="frt-20240331.xsd#frt_ShareTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_frt_ShareTypeAxis_2a8ac5bd-2fdb-4651-9322-903519557850" xlink:to="loc_frt_ShareTypeDomain_2a8ac5bd-2fdb-4651-9322-903519557850_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_ShareTypeDomain_f6a00a70-51b3-4664-9cf8-05a2cbbada72" xlink:href="frt-20240331.xsd#frt_ShareTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_frt_ShareTypeAxis_2a8ac5bd-2fdb-4651-9322-903519557850" xlink:to="loc_frt_ShareTypeDomain_f6a00a70-51b3-4664-9cf8-05a2cbbada72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_StockOptionsMember_1dde2f57-6388-431c-aa69-660a4a32dd8c" xlink:href="frt-20240331.xsd#frt_StockOptionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ShareTypeDomain_f6a00a70-51b3-4664-9cf8-05a2cbbada72" xlink:to="loc_frt_StockOptionsMember_1dde2f57-6388-431c-aa69-660a4a32dd8c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PerformanceBasedUnvestedSharesMember_e0ee913a-072b-41af-aa54-9c576817cf56" xlink:href="frt-20240331.xsd#frt_PerformanceBasedUnvestedSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_ShareTypeDomain_f6a00a70-51b3-4664-9cf8-05a2cbbada72" xlink:to="loc_frt_PerformanceBasedUnvestedSharesMember_e0ee913a-072b-41af-aa54-9c576817cf56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_bf7dec97-23c0-4689-973b-5e10595af148" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_bf7dec97-23c0-4689-973b-5e10595af148" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_bf7dec97-23c0-4689-973b-5e10595af148_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_bf7dec97-23c0-4689-973b-5e10595af148" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_bf7dec97-23c0-4689-973b-5e10595af148_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_8cd43b0e-2761-4b46-a518-aa6e53f2ebe9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_bf7dec97-23c0-4689-973b-5e10595af148" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_8cd43b0e-2761-4b46-a518-aa6e53f2ebe9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_us-gaap_StatementClassOfStockAxis_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7" xlink:to="loc_us-gaap_ClassOfStockDomain_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_844717d3-7993-49c5-a9bf-ab8ee4800fb2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_74ae6aa4-bdc5-4bbd-8c52-b5e1ffb702f7" xlink:to="loc_us-gaap_ClassOfStockDomain_844717d3-7993-49c5-a9bf-ab8ee4800fb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_681c88b3-8a62-4b67-a351-632bf98c6db3" xlink:href="frt-20240331.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_844717d3-7993-49c5-a9bf-ab8ee4800fb2" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_681c88b3-8a62-4b67-a351-632bf98c6db3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredUnitsMember_9d9d4922-9b40-4e29-9d10-03ce3f4ca6a6" xlink:href="frt-20240331.xsd#frt_PreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_844717d3-7993-49c5-a9bf-ab8ee4800fb2" xlink:to="loc_frt_PreferredUnitsMember_9d9d4922-9b40-4e29-9d10-03ce3f4ca6a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_23e332f6-e45a-4fa2-b53d-11fa8c394e1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_us-gaap_DebtInstrumentAxis_23e332f6-e45a-4fa2-b53d-11fa8c394e1e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_23e332f6-e45a-4fa2-b53d-11fa8c394e1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_23e332f6-e45a-4fa2-b53d-11fa8c394e1e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_23e332f6-e45a-4fa2-b53d-11fa8c394e1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4b6f4134-3d75-412a-8eef-6756099640aa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_23e332f6-e45a-4fa2-b53d-11fa8c394e1e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4b6f4134-3d75-412a-8eef-6756099640aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_Senior3Point25PercentNotesMember_ce92456b-94a3-430b-ad2d-872f0b3cbafc" xlink:href="frt-20240331.xsd#frt_Senior3Point25PercentNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4b6f4134-3d75-412a-8eef-6756099640aa" xlink:to="loc_frt_Senior3Point25PercentNotesMember_ce92456b-94a3-430b-ad2d-872f0b3cbafc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_035b9cf0-4818-496f-aab9-a604b3978535" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_035b9cf0-4818-496f-aab9-a604b3978535" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_035b9cf0-4818-496f-aab9-a604b3978535_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_035b9cf0-4818-496f-aab9-a604b3978535" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_035b9cf0-4818-496f-aab9-a604b3978535_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_99fb94d5-1246-45fc-bbe5-765102a19b78" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_035b9cf0-4818-496f-aab9-a604b3978535" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_99fb94d5-1246-45fc-bbe5-765102a19b78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_583add5d-33cd-4433-9a29-f00ba162c4ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_99fb94d5-1246-45fc-bbe5-765102a19b78" xlink:to="loc_us-gaap_ConvertibleDebtMember_583add5d-33cd-4433-9a29-f00ba162c4ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d092d654-0492-4882-8eab-8b97a7180c5d" xlink:to="loc_srt_ConsolidatedEntitiesAxis_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb" xlink:to="loc_srt_ConsolidatedEntitiesDomain_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_cee252bf-4efc-48a8-9d12-5d6a8a7412ce" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_b12dd9b8-44e2-4f7e-9a8e-e0d72e73f0eb" xlink:to="loc_srt_ConsolidatedEntitiesDomain_cee252bf-4efc-48a8-9d12-5d6a8a7412ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_9a4e24af-ca6f-4168-a78b-45eaf460aa44" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_cee252bf-4efc-48a8-9d12-5d6a8a7412ce" xlink:to="loc_srt_PartnershipInterestMember_9a4e24af-ca6f-4168-a78b-45eaf460aa44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights_7897d6cc-4611-4742-95ed-82753e6ddd39" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights_7897d6cc-4611-4742-95ed-82753e6ddd39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_IncrementalCommonUnitsAttributableToParticipatingNonvestedShares_7543200c-07b0-4bdf-b40e-4d0df3bc9af2" xlink:href="frt-20240331.xsd#frt_IncrementalCommonUnitsAttributableToParticipatingNonvestedShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_frt_IncrementalCommonUnitsAttributableToParticipatingNonvestedShares_7543200c-07b0-4bdf-b40e-4d0df3bc9af2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d325d5ca-12f7-4d0e-9231-a901536e08c5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d325d5ca-12f7-4d0e-9231-a901536e08c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitUnits_6a556284-1826-430c-9895-22b71576e103" xlink:href="frt-20240331.xsd#frt_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_frt_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitUnits_6a556284-1826-430c-9895-22b71576e103" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_d7e7fec2-27e0-428c-99e3-31ad086e4bcb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_d7e7fec2-27e0-428c-99e3-31ad086e4bcb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredUnitDistributionRatePercentage_8380f3a3-0165-4f86-9cc5-14c3dcc0edc4" xlink:href="frt-20240331.xsd#frt_PreferredUnitDistributionRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_frt_PreferredUnitDistributionRatePercentage_8380f3a3-0165-4f86-9cc5-14c3dcc0edc4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_08317793-4b87-4b31-94a9-5dec0ef93bcb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4f34d82e-5fc4-4350-bc2a-94b7d56c1eda" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_08317793-4b87-4b31-94a9-5dec0ef93bcb" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/EarningsPerShareAndUnitScheduleOfEarningsPerShareDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#EarningsPerShareAndUnitScheduleOfEarningsPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/EarningsPerShareAndUnitScheduleOfEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_93a95536-8289-4da0-836d-6a22ce3077b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_StatementTable_93a95536-8289-4da0-836d-6a22ce3077b0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_bcfb2c18-f7f9-4214-81bc-8152f9d430cc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_93a95536-8289-4da0-836d-6a22ce3077b0" xlink:to="loc_srt_ConsolidatedEntitiesAxis_bcfb2c18-f7f9-4214-81bc-8152f9d430cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_bcfb2c18-f7f9-4214-81bc-8152f9d430cc_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_bcfb2c18-f7f9-4214-81bc-8152f9d430cc" xlink:to="loc_srt_ConsolidatedEntitiesDomain_bcfb2c18-f7f9-4214-81bc-8152f9d430cc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_e9008c68-9819-449f-83f1-3a9f67f311a9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_bcfb2c18-f7f9-4214-81bc-8152f9d430cc" xlink:to="loc_srt_ConsolidatedEntitiesDomain_e9008c68-9819-449f-83f1-3a9f67f311a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_3e5a85e2-90e9-497c-8c4e-da3d5d6e6856" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_e9008c68-9819-449f-83f1-3a9f67f311a9" xlink:to="loc_srt_PartnershipInterestMember_3e5a85e2-90e9-497c-8c4e-da3d5d6e6856" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_93a95536-8289-4da0-836d-6a22ce3077b0" xlink:to="loc_us-gaap_StatementClassOfStockAxis_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c" xlink:to="loc_us-gaap_ClassOfStockDomain_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ac53ed5a-99fe-42cd-881d-98ce16d55128" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_8b68eba4-8907-4f5e-ae7b-3e0b9ab3027c" xlink:to="loc_us-gaap_ClassOfStockDomain_ac53ed5a-99fe-42cd-881d-98ce16d55128" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_PreferredUnitsMember_3b5326c2-bcbb-4f85-9d3e-3f4f17cf5ca1" xlink:href="frt-20240331.xsd#frt_PreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ac53ed5a-99fe-42cd-881d-98ce16d55128" xlink:to="loc_frt_PreferredUnitsMember_3b5326c2-bcbb-4f85-9d3e-3f4f17cf5ca1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_5c7116bb-4f75-4d30-8c6a-0036257e92ed" xlink:href="frt-20240331.xsd#frt_A5417Series1CumulativeConvertiblePreferredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ac53ed5a-99fe-42cd-881d-98ce16d55128" xlink:to="loc_frt_A5417Series1CumulativeConvertiblePreferredMember_5c7116bb-4f75-4d30-8c6a-0036257e92ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_c7602e0e-4d67-45bb-b8fc-f6b7bfab32cd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_ProfitLoss_c7602e0e-4d67-45bb-b8fc-f6b7bfab32cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_f72a4c4c-f8b5-408a-9870-ca9823cf229a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_f72a4c4c-f8b5-408a-9870-ca9823cf229a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_DistributionsDeclaredToPreferredUnitHolders_fb4518db-8791-4367-b894-2f4351aa0488" xlink:href="frt-20240331.xsd#frt_DistributionsDeclaredToPreferredUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_DistributionsDeclaredToPreferredUnitHolders_fb4518db-8791-4367-b894-2f4351aa0488" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_d1a59ff9-3d79-4042-8fd2-cf1e0a8fcc32" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_d1a59ff9-3d79-4042-8fd2-cf1e0a8fcc32" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EarningsAllocatedToUnvestedShares_6ce52683-be69-4a82-9795-412faedb8274" xlink:href="frt-20240331.xsd#frt_EarningsAllocatedToUnvestedShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_EarningsAllocatedToUnvestedShares_6ce52683-be69-4a82-9795-412faedb8274" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EarningsAllocatedToUnvestedUnits_e694e377-3356-422a-a703-e6a7c5743ff5" xlink:href="frt-20240331.xsd#frt_EarningsAllocatedToUnvestedUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_EarningsAllocatedToUnvestedUnits_e694e377-3356-422a-a703-e6a7c5743ff5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetIncomeAvailableForCommonShareholdersBasic_8dd10e05-a417-4bce-b818-350d1ee9ab41" xlink:href="frt-20240331.xsd#frt_NetIncomeAvailableForCommonShareholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_NetIncomeAvailableForCommonShareholdersBasic_8dd10e05-a417-4bce-b818-350d1ee9ab41" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_776627eb-0d8a-4bbe-877d-58103f2580ff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_776627eb-0d8a-4bbe-877d-58103f2580ff" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetIncomeAvailableForCommonUnitHoldersBasic_5af538d6-abf5-4e31-b7f6-3ec403bfc34a" xlink:href="frt-20240331.xsd#frt_NetIncomeAvailableForCommonUnitHoldersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_NetIncomeAvailableForCommonUnitHoldersBasic_5af538d6-abf5-4e31-b7f6-3ec403bfc34a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetIncomeAvailableForCommonUnitsOutstandingDiluted_7d639989-1ee8-4be1-85d1-ec2f4b3ef9de" xlink:href="frt-20240331.xsd#frt_NetIncomeAvailableForCommonUnitsOutstandingDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_NetIncomeAvailableForCommonUnitsOutstandingDiluted_7d639989-1ee8-4be1-85d1-ec2f4b3ef9de" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_0159f4f7-3474-46e0-8bb1-8bcb88ade8be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_0159f4f7-3474-46e0-8bb1-8bcb88ade8be" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_672a94b6-b7c5-4601-a4c5-632e035dc175" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_672a94b6-b7c5-4601-a4c5-632e035dc175" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic_11ab2ef3-ed9d-45ef-8d5d-a6ba8c5f1c75" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipAndGeneralPartnershipUnitsOutstandingBasic_11ab2ef3-ed9d-45ef-8d5d-a6ba8c5f1c75" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_WeightedAverageCommonUnitsOutstandingDiluted_979f55b8-9114-4eac-bfcf-d132abb3719f" xlink:href="frt-20240331.xsd#frt_WeightedAverageCommonUnitsOutstandingDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_WeightedAverageCommonUnitsOutstandingDiluted_979f55b8-9114-4eac-bfcf-d132abb3719f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareReconciliationAbstract_b52888b3-47ae-45d7-9b3c-811a00905cfc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareReconciliationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_us-gaap_EarningsPerShareReconciliationAbstract_b52888b3-47ae-45d7-9b3c-811a00905cfc" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_a2fe8f24-ecfb-4c03-bbc1-327bcb6d0a4e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_b52888b3-47ae-45d7-9b3c-811a00905cfc" xlink:to="loc_us-gaap_EarningsPerShareBasic_a2fe8f24-ecfb-4c03-bbc1-327bcb6d0a4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_a2e1d1e5-572e-4761-ab2a-ea0ee79d4cc9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_b52888b3-47ae-45d7-9b3c-811a00905cfc" xlink:to="loc_us-gaap_EarningsPerShareDiluted_a2e1d1e5-572e-4761-ab2a-ea0ee79d4cc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_bd477bd0-102f-4bab-a5f3-d6ba21a72a0a" xlink:href="frt-20240331.xsd#frt_EARNINGSPERCOMMONUNITBASICAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0b237ebc-4797-4690-a464-6b96960636f5" xlink:to="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_bd477bd0-102f-4bab-a5f3-d6ba21a72a0a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax_d3cbc733-1677-430b-be6c-fb917c7f8e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_bd477bd0-102f-4bab-a5f3-d6ba21a72a0a" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerOutstandingGeneralPartnershipUnitNetOfTax_d3cbc733-1677-430b-be6c-fb917c7f8e6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax_1824ad11-6312-4a62-be0f-480c79b41299" xlink:href="frt-20240331.xsd#frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frt_EARNINGSPERCOMMONUNITBASICAbstract_bd477bd0-102f-4bab-a5f3-d6ba21a72a0a" xlink:to="loc_frt_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitDilutedNetOfTax_1824ad11-6312-4a62-be0f-480c79b41299" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.federalrealty.com/role/SubsequentEventDetails" xlink:type="simple" xlink:href="frt-20240331.xsd#SubsequentEventDetails"/>
  <link:definitionLink xlink:role="http://www.federalrealty.com/role/SubsequentEventDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_ccf55fc8-b970-4205-ad21-28899f92e933" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_ef0facdd-37a2-4116-8447-ed9198e49fbe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_ccf55fc8-b970-4205-ad21-28899f92e933" xlink:to="loc_us-gaap_SubsequentEventTable_ef0facdd-37a2-4116-8447-ed9198e49fbe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_22e3aceb-4c15-4ec3-a607-ef6254ef24ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_ef0facdd-37a2-4116-8447-ed9198e49fbe" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_22e3aceb-4c15-4ec3-a607-ef6254ef24ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_22e3aceb-4c15-4ec3-a607-ef6254ef24ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_22e3aceb-4c15-4ec3-a607-ef6254ef24ae" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_22e3aceb-4c15-4ec3-a607-ef6254ef24ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_23e978cc-a431-4f7d-ba46-1ffd8cad403e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_22e3aceb-4c15-4ec3-a607-ef6254ef24ae" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_23e978cc-a431-4f7d-ba46-1ffd8cad403e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_f672b712-5cfa-4210-afe8-884331ed143c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_23e978cc-a431-4f7d-ba46-1ffd8cad403e" xlink:to="loc_us-gaap_SubsequentEventMember_f672b712-5cfa-4210-afe8-884331ed143c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_12af4574-bc25-43b7-bb86-8113537d6163" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_ef0facdd-37a2-4116-8447-ed9198e49fbe" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_12af4574-bc25-43b7-bb86-8113537d6163" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_12af4574-bc25-43b7-bb86-8113537d6163_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_12af4574-bc25-43b7-bb86-8113537d6163" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_12af4574-bc25-43b7-bb86-8113537d6163_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_cc8e71de-95a6-4055-999d-377cb1112873" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_12af4574-bc25-43b7-bb86-8113537d6163" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_cc8e71de-95a6-4055-999d-377cb1112873" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_CocoWalkMember_32e50b46-1841-4472-bce9-51fd6f52ad8e" xlink:href="frt-20240331.xsd#frt_CocoWalkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_cc8e71de-95a6-4055-999d-377cb1112873" xlink:to="loc_frt_CocoWalkMember_32e50b46-1841-4472-bce9-51fd6f52ad8e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_NoncontrollingInterestInPartnership_ec9695f9-802a-4a74-a3ef-37c814a9fb37" xlink:href="frt-20240331.xsd#frt_NoncontrollingInterestInPartnership"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_ccf55fc8-b970-4205-ad21-28899f92e933" xlink:to="loc_frt_NoncontrollingInterestInPartnership_ec9695f9-802a-4a74-a3ef-37c814a9fb37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_d2901ebb-cc8b-48d4-82f1-62da256f9c5d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_ccf55fc8-b970-4205-ad21-28899f92e933" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_d2901ebb-cc8b-48d4-82f1-62da256f9c5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frt_OwnershipInterestSubsequentToAcquisition_05d4d9d0-f108-4419-a800-f90287035816" xlink:href="frt-20240331.xsd#frt_OwnershipInterestSubsequentToAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_ccf55fc8-b970-4205-ad21-28899f92e933" xlink:to="loc_frt_OwnershipInterestSubsequentToAcquisition_05d4d9d0-f108-4419-a800-f90287035816" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
