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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a11b78-2159-7c3f-8788-988875a327b3,g:b9e3fed8-6d5a-4f9e-8ee8-3ad262d42cb8-->
<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://fhlb.com/role/Cover" xlink:type="simple" xlink:href="fhlbd-20261005.xsd#Cover"/>
  <link:definitionLink xlink:role="http://fhlb.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_01a11b78-2159-713c-85b2-fefabee65cf0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntitiesTable_01a11b78-2159-713c-85b2-fefabee65cf0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_01a11b78-2159-7672-8144-2818eff889f3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_01a11b78-2159-713c-85b2-fefabee65cf0" xlink:to="loc_dei_LegalEntityAxis_01a11b78-2159-7672-8144-2818eff889f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a11b78-2159-7672-8144-2818eff889f3_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_01a11b78-2159-7672-8144-2818eff889f3" xlink:to="loc_dei_EntityDomain_01a11b78-2159-7672-8144-2818eff889f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a11b78-2159-767f-856c-181029ecdcfb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_01a11b78-2159-7672-8144-2818eff889f3" xlink:to="loc_dei_EntityDomain_01a11b78-2159-767f-856c-181029ecdcfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a11b78-2159-7a31-9287-6eeecb561422" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_AmendmentFlag_01a11b78-2159-7a31-9287-6eeecb561422" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a11b78-2159-79c4-85eb-cbe7438339f0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_DocumentType_01a11b78-2159-79c4-85eb-cbe7438339f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a11b78-2159-7652-a64a-06625c830e43" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_DocumentPeriodEndDate_01a11b78-2159-7652-a64a-06625c830e43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a11b78-2159-7c15-a0d5-3f62c7eef951" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityRegistrantName_01a11b78-2159-7c15-a0d5-3f62c7eef951" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a11b78-2159-70e4-91de-ba10b0ce3092" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityCentralIndexKey_01a11b78-2159-70e4-91de-ba10b0ce3092" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a11b78-2159-7cf5-b8a5-f247b3e4960e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityFileNumber_01a11b78-2159-7cf5-b8a5-f247b3e4960e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a11b78-2159-7a16-8106-4e93d66c7ecd" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a11b78-2159-7a16-8106-4e93d66c7ecd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a11b78-2159-7a20-99e7-3f2e71b1b5ee" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityAddressAddressLine1_01a11b78-2159-7a20-99e7-3f2e71b1b5ee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a11b78-2159-7d1f-b66c-f8c472b9c571" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityAddressCityOrTown_01a11b78-2159-7d1f-b66c-f8c472b9c571" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a11b78-2159-7c35-ac3c-18c0986e533f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityAddressStateOrProvince_01a11b78-2159-7c35-ac3c-18c0986e533f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a11b78-2159-70d2-80b7-da63eb40d58c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityAddressPostalZipCode_01a11b78-2159-70d2-80b7-da63eb40d58c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a11b78-2159-7738-8cdb-58a7323b6e19" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_CityAreaCode_01a11b78-2159-7738-8cdb-58a7323b6e19" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a11b78-2159-77e6-a2a0-caaf93772115" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_LocalPhoneNumber_01a11b78-2159-77e6-a2a0-caaf93772115" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a11b78-2159-77db-b4af-d55b230cb9e4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_WrittenCommunications_01a11b78-2159-77db-b4af-d55b230cb9e4" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a11b78-2159-7a84-967d-8e87b28ca1d3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_SolicitingMaterial_01a11b78-2159-7a84-967d-8e87b28ca1d3" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a11b78-2159-7d70-ab9b-a779e980a5b9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_PreCommencementTenderOffer_01a11b78-2159-7d70-ab9b-a779e980a5b9" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a11b78-2159-728b-8e7c-46162a23eda3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a11b78-2159-728b-8e7c-46162a23eda3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a11b78-2159-7447-8afa-2139ae9a90e1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a11b78-2159-7447-8afa-2139ae9a90e1" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a11b78-2159-7bb3-85d0-b11f79cacebb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a11b78-2159-7190-85f8-c53690ccfb8c" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a11b78-2159-7bb3-85d0-b11f79cacebb" xlink:type="arc" order="18"/>
  </link:definitionLink>
</link:linkbase>
