<?xml version="1.0" encoding="us-ascii"?>
<!-- XBRL document created with Praxa -->
<!-- Copyright (c) 2026 Praxa LLC. All Rights Reserved.-->
<!-- Creation Date: 2026-09-29T14:41:22.9353+00:00 -->
<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:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/JudgmentDebtPayableDetails" xlink:href="sgly-20260630.xsd#JudgmentDebtPayableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/ClassActionSettlementDetails" xlink:href="sgly-20260630.xsd#ClassActionSettlementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingParentheticalsDetails" xlink:href="sgly-20260630.xsd#EquityScheduleofWarrantsOutstandingParentheticalsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/CommitmentsandContingenciesDetails" xlink:href="sgly-20260630.xsd#CommitmentsandContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingDetails" xlink:href="sgly-20260630.xsd#EquityScheduleofWarrantsOutstandingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingandExercisableDetails" xlink:href="sgly-20260630.xsd#EquityScheduleofWarrantsOutstandingandExercisableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsDetails" xlink:href="sgly-20260630.xsd#RelatedPartyBalancesandTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/DispositionofSubsidiariesDetails" xlink:href="sgly-20260630.xsd#DispositionofSubsidiariesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/SubsequentEventsDetails" xlink:href="sgly-20260630.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/ConsolidatedStatementsofChangesInEquity" xlink:href="sgly-20260630.xsd#ConsolidatedStatementsofChangesInEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/OrganizationandNatureofBusinessDetails" xlink:href="sgly-20260630.xsd#OrganizationandNatureofBusinessDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/ConsolidatedBalanceSheets" xlink:href="sgly-20260630.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofPreTaxIncomeDisaggregatedDetails" xlink:href="sgly-20260630.xsd#IncomeTaxesScheduleofPreTaxIncomeDisaggregatedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/OrganizationandNatureofBusinessScheduleofSubsidiariesDetails" xlink:href="sgly-20260630.xsd#OrganizationandNatureofBusinessScheduleofSubsidiariesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesDetails" xlink:href="sgly-20260630.xsd#SummaryofSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetails" xlink:href="sgly-20260630.xsd#SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofDisaggregatedRevenueStreamsDetails" xlink:href="sgly-20260630.xsd#SummaryofSignificantAccountingPoliciesScheduleofDisaggregatedRevenueStreamsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetails" xlink:href="sgly-20260630.xsd#SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/EquityDetails" xlink:href="sgly-20260630.xsd#EquityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/NonControllingInterestScheduleofNonControllingInterestDetails" xlink:href="sgly-20260630.xsd#NonControllingInterestScheduleofNonControllingInterestDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsScheduleofDuefromRelatedPartiesDetails" xlink:href="sgly-20260630.xsd#RelatedPartyBalancesandTransactionsScheduleofDuefromRelatedPartiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesDetails" xlink:href="sgly-20260630.xsd#IncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/ConcentrationsDetails" xlink:href="sgly-20260630.xsd#ConcentrationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/DispositionofSubsidiariesScheduleofReconciliationofDispositionofSubsidiariesDetails" xlink:href="sgly-20260630.xsd#DispositionofSubsidiariesScheduleofReconciliationofDispositionofSubsidiariesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofIncomeTaxExpensesDetails" xlink:href="sgly-20260630.xsd#IncomeTaxesScheduleofIncomeTaxExpensesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofDeferredTaxAssetsDetails" xlink:href="sgly-20260630.xsd#IncomeTaxesScheduleofDeferredTaxAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetails" xlink:href="sgly-20260630.xsd#RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/AdvancestoSuppliersScheduleofAdvancestoSuppliersDetails" xlink:href="sgly-20260630.xsd#AdvancestoSuppliersScheduleofAdvancestoSuppliersDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://singularityfuturetechnologyltd.com/20260630/role/LoansfromThirdPartiesDetails" xlink:href="sgly-20260630.xsd#LoansfromThirdPartiesDetails" xlink:type="simple" />
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/JudgmentDebtPayableDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_JingShanMember" xlink:label="sgly_JingShanMember_2103" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_MrHuangMember" xlink:label="sgly_MrHuangMember_2099" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShanMember" xlink:label="sgly_ShanMember_2105" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_2109" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1577" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems_1580" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentIncreaseAccruedInterest" xlink:label="us-gaap_DebtInstrumentIncreaseAccruedInterest_1581" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForLegalSettlements" xlink:label="us-gaap_PaymentsForLegalSettlements_1582" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1583" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_VirginiaContemptJudgmentPayableAmount" xlink:label="sgly_VirginiaContemptJudgmentPayableAmount_2104" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_VirginiaFeeJudgmentPayableAmount" xlink:label="sgly_VirginiaFeeJudgmentPayableAmount_2106" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_2107" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2108" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentsAbstract" xlink:label="us-gaap_DebtInstrumentsAbstract_1574" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_JudgmentDebtPayableDetailsTable" xlink:label="sgly_JudgmentDebtPayableDetailsTable_1575" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis_1576" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1577_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2108_default" />
    <link:definitionArc xlink:type="arc" order="244.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_1577" xlink:to="sgly_JingShanMember_2103" />
    <link:definitionArc xlink:type="arc" order="240.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_1577" xlink:to="sgly_MrHuangMember_2099" />
    <link:definitionArc xlink:type="arc" order="246.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_1577" xlink:to="sgly_ShanMember_2105" />
    <link:definitionArc xlink:type="arc" order="250.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain_2108" xlink:to="us-gaap_SubsequentEventMember_2109" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis_1576" xlink:to="us-gaap_DebtInstrumentNameDomain_1577" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="us-gaap_DebtInstrumentIncreaseAccruedInterest_1581" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="us-gaap_PaymentsForLegalSettlements_1582" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1583" />
    <link:definitionArc xlink:type="arc" order="245.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="sgly_VirginiaContemptJudgmentPayableAmount_2104" />
    <link:definitionArc xlink:type="arc" order="247.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="sgly_VirginiaFeeJudgmentPayableAmount_2106" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_JudgmentDebtPayableDetailsTable_1575" xlink:to="us-gaap_SubsequentEventTypeAxis_2107" />
    <link:definitionArc xlink:type="arc" order="249.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis_2107" xlink:to="us-gaap_SubsequentEventTypeDomain_2108" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems_1580" xlink:to="sgly_JudgmentDebtPayableDetailsTable_1575" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_JudgmentDebtPayableDetailsTable_1575" xlink:to="us-gaap_DebtInstrumentAxis_1576" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis_1576" xlink:to="us-gaap_DebtInstrumentNameDomain_1577_default" />
    <link:definitionArc xlink:type="arc" order="249.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis_2107" xlink:to="us-gaap_SubsequentEventTypeDomain_2108_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/ClassActionSettlementDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_2048" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2111" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AmendedSettlementAgreementMember" xlink:label="sgly_AmendedSettlementAgreementMember_2112" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OptionIndexedToIssuersEquityLineItems" xlink:label="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AdditionalSettlementPayments" xlink:label="sgly_AdditionalSettlementPayments_1974" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ClassActionSettlementAbstract" xlink:label="sgly_ClassActionSettlementAbstract_1585" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ClassActionSettlementDetailsTable" xlink:label="sgly_ClassActionSettlementDetailsTable_1586" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EscrowDeposit" xlink:label="us-gaap_EscrowDeposit_1604" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_2046" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2047" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForLegalSettlements" xlink:label="us-gaap_PaymentsForLegalSettlements_2053" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_2110" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositAssets" xlink:label="us-gaap_DepositAssets_2113" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2111_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2047_default" />
    <link:definitionArc xlink:type="arc" order="204.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain_2047" xlink:to="us-gaap_SubsequentEventMember_2048" />
    <link:definitionArc xlink:type="arc" order="252.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis_2110" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2111" />
    <link:definitionArc xlink:type="arc" order="253.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2111" xlink:to="sgly_AmendedSettlementAgreementMember_2112" />
    <link:definitionArc xlink:type="arc" order="135.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" xlink:to="sgly_AdditionalSettlementPayments_1974" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" xlink:to="sgly_ClassActionSettlementDetailsTable_1586" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" xlink:to="us-gaap_EscrowDeposit_1604" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ClassActionSettlementDetailsTable_1586" xlink:to="us-gaap_SubsequentEventTypeAxis_2046" />
    <link:definitionArc xlink:type="arc" order="203.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis_2046" xlink:to="us-gaap_SubsequentEventTypeDomain_2047" />
    <link:definitionArc xlink:type="arc" order="208.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" xlink:to="us-gaap_PaymentsForLegalSettlements_2053" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ClassActionSettlementDetailsTable_1586" xlink:to="us-gaap_TypeOfArrangementAxis_2110" />
    <link:definitionArc xlink:type="arc" order="254.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityLineItems_1597" xlink:to="us-gaap_DepositAssets_2113" />
    <link:definitionArc xlink:type="arc" order="252.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TypeOfArrangementAxis_2110" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2111_default" />
    <link:definitionArc xlink:type="arc" order="203.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis_2046" xlink:to="us-gaap_SubsequentEventTypeDomain_2047_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/EquityDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember_1612" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandAndTwentyFiveWarrantMember" xlink:label="sgly_TwoThousandAndTwentyFiveWarrantMember_1980" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandTwentyOneWarrantsMember" xlink:label="sgly_TwoThousandTwentyOneWarrantsMember_1618" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ZhikangHuangMember" xlink:label="sgly_ZhikangHuangMember_1621" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_1632" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ClosingBidPriceOfCommonStock" xlink:label="sgly_ClosingBidPriceOfCommonStock_1633" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_1634" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_1635" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued" xlink:label="us-gaap_CommonStockSharesIssued_1636" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SubsequentlyReturnedFunds" xlink:label="sgly_SubsequentlyReturnedFunds_1637" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_WarrantsIssuable" xlink:label="sgly_WarrantsIssuable_1638" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityNoteStockSplit" xlink:label="us-gaap_StockholdersEquityNoteStockSplit_2054" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ExercisePriceStockSplit" xlink:label="sgly_ExercisePriceStockSplit_2055" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_2056" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="us-gaap_ScheduleOfStockByClassTable_1609" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="us-gaap_StatementClassOfStockAxis_1610" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="us-gaap_ClassOfStockDomain_1611" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_1616" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_1625" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_1626" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_1627" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstandingTerm" xlink:label="us-gaap_WarrantsAndRightsOutstandingTerm_1628" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_1629" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PurchasePriceForEachShareOfCommonStock" xlink:label="sgly_PurchasePriceForEachShareOfCommonStock_1630" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_WarrantsToPurchaseOfCommonStock" xlink:label="sgly_WarrantsToPurchaseOfCommonStock_1631" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForLegalSettlements" xlink:label="us-gaap_PaymentsForLegalSettlements_1640" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1641" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityAbstract" xlink:label="us-gaap_EquityAbstract_1608" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1617" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis_1619" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1620" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems" xlink:label="us-gaap_ClassOfStockLineItems_1622" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="us-gaap_StockIssuedDuringPeriodSharesOther_1623" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharePrice" xlink:label="us-gaap_SharePrice_1624" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="us-gaap_ClassOfStockDomain_1611_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1617_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1620_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockDomain_1611" xlink:to="us-gaap_CommonStockMember_1612" />
    <link:definitionArc xlink:type="arc" order="141.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1617" xlink:to="sgly_TwoThousandAndTwentyFiveWarrantMember_1980" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1617" xlink:to="sgly_TwoThousandTwentyOneWarrantsMember_1618" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_1620" xlink:to="sgly_ZhikangHuangMember_1621" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_1632" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_ClosingBidPriceOfCommonStock_1633" />
    <link:definitionArc xlink:type="arc" order="21.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_1634" />
    <link:definitionArc xlink:type="arc" order="22.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_1635" />
    <link:definitionArc xlink:type="arc" order="23.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_CommonStockSharesIssued_1636" />
    <link:definitionArc xlink:type="arc" order="24.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_SubsequentlyReturnedFunds_1637" />
    <link:definitionArc xlink:type="arc" order="25.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_WarrantsIssuable_1638" />
    <link:definitionArc xlink:type="arc" order="209.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_StockholdersEquityNoteStockSplit_2054" />
    <link:definitionArc xlink:type="arc" order="210.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_ExercisePriceStockSplit_2055" />
    <link:definitionArc xlink:type="arc" order="211.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_StockholdersEquityReverseStockSplit_2056" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ScheduleOfStockByClassTable_1609" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfStockByClassTable_1609" xlink:to="us-gaap_StatementClassOfStockAxis_1610" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementClassOfStockAxis_1610" xlink:to="us-gaap_ClassOfStockDomain_1611" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfStockByClassTable_1609" xlink:to="us-gaap_ClassOfWarrantOrRightAxis_1616" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_1625" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_1626" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_1627" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_WarrantsAndRightsOutstandingTerm_1628" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_1629" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_PurchasePriceForEachShareOfCommonStock_1630" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="sgly_WarrantsToPurchaseOfCommonStock_1631" />
    <link:definitionArc xlink:type="arc" order="27.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_PaymentsForLegalSettlements_1640" />
    <link:definitionArc xlink:type="arc" order="28.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1641" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1616" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1617" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfStockByClassTable_1609" xlink:to="us-gaap_DebtInstrumentAxis_1619" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis_1619" xlink:to="us-gaap_DebtInstrumentNameDomain_1620" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_StockIssuedDuringPeriodSharesOther_1623" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockLineItems_1622" xlink:to="us-gaap_SharePrice_1624" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementClassOfStockAxis_1610" xlink:to="us-gaap_ClassOfStockDomain_1611_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1616" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1617_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis_1619" xlink:to="us-gaap_DebtInstrumentNameDomain_1620_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingParentheticalsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandAndTwentyFiveWarrantMember" xlink:label="sgly_TwoThousandAndTwentyFiveWarrantMember_1988" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandAndTwentyOneWarrantMember" xlink:label="sgly_TwoThousandAndTwentyOneWarrantMember_1405" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1930" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfWarrantsOutstandingAbstract" xlink:label="sgly_ScheduleOfWarrantsOutstandingAbstract_1402" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="us-gaap_ClassOfWarrantOrRightTable_1403" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_1404" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1406" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_1407" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1930_default" />
    <link:definitionArc xlink:type="arc" order="149.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1930" xlink:to="sgly_TwoThousandAndTwentyFiveWarrantMember_1988" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1930" xlink:to="sgly_TwoThousandAndTwentyOneWarrantMember_1405" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1404" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1930" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1406" xlink:to="us-gaap_ClassOfWarrantOrRightTable_1403" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ClassOfWarrantOrRightTable_1403" xlink:to="us-gaap_ClassOfWarrantOrRightAxis_1404" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1406" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_1407" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1404" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1930_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/CommitmentsandContingenciesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AmendedSettlementAgreementMember" xlink:label="sgly_AmendedSettlementAgreementMember_2003" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_MrHuangMember" xlink:label="sgly_MrHuangMember_2119" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShanMember" xlink:label="sgly_ShanMember_2122" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2002" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_2012" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_FreightShippingServicesMember" xlink:label="sgly_FreightShippingServicesMember_1662" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AdditionalSettlementPayments" xlink:label="sgly_AdditionalSettlementPayments_2114" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CivilMonetaryPenalty" xlink:label="sgly_CivilMonetaryPenalty_1685" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_1643" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_2001" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositAssets" xlink:label="us-gaap_DepositAssets_2007" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_2010" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2011" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentIncreaseAccruedInterest" xlink:label="us-gaap_DebtInstrumentIncreaseAccruedInterest_2116" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis_2117" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_2118" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_VirginiaContemptJudgmentPayableAmount" xlink:label="sgly_VirginiaContemptJudgmentPayableAmount_2120" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_VirginiaFeeJudgmentPayableAmount" xlink:label="sgly_VirginiaFeeJudgmentPayableAmount_2121" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CommitmentsandContingenciesDetailsTable" xlink:label="sgly_CommitmentsandContingenciesDetailsTable_1644" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis_1660" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_1661" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EscrowDeposit" xlink:label="us-gaap_EscrowDeposit_1673" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems" xlink:label="us-gaap_LossContingenciesLineItems_1666" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForLegalSettlements" xlink:label="us-gaap_PaymentsForLegalSettlements_1669" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1681" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireLoansReceivable" xlink:label="us-gaap_PaymentsToAcquireLoansReceivable_1683" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues_1684" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2002_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2011_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_2118_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_1661_default" />
    <link:definitionArc xlink:type="arc" order="162.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2002" xlink:to="sgly_AmendedSettlementAgreementMember_2003" />
    <link:definitionArc xlink:type="arc" order="260.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_2118" xlink:to="sgly_MrHuangMember_2119" />
    <link:definitionArc xlink:type="arc" order="263.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_2118" xlink:to="sgly_ShanMember_2122" />
    <link:definitionArc xlink:type="arc" order="161.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis_2001" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2002" />
    <link:definitionArc xlink:type="arc" order="171.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain_2011" xlink:to="us-gaap_SubsequentEventMember_2012" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain_1661" xlink:to="sgly_FreightShippingServicesMember_1662" />
    <link:definitionArc xlink:type="arc" order="255.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="sgly_AdditionalSettlementPayments_2114" />
    <link:definitionArc xlink:type="arc" order="28.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="sgly_CivilMonetaryPenalty_1685" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_CommitmentsandContingenciesDetailsTable_1644" xlink:to="us-gaap_TypeOfArrangementAxis_2001" />
    <link:definitionArc xlink:type="arc" order="166.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_DepositAssets_2007" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_CommitmentsandContingenciesDetailsTable_1644" xlink:to="us-gaap_SubsequentEventTypeAxis_2010" />
    <link:definitionArc xlink:type="arc" order="170.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis_2010" xlink:to="us-gaap_SubsequentEventTypeDomain_2011" />
    <link:definitionArc xlink:type="arc" order="257.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_DebtInstrumentIncreaseAccruedInterest_2116" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_CommitmentsandContingenciesDetailsTable_1644" xlink:to="us-gaap_DebtInstrumentAxis_2117" />
    <link:definitionArc xlink:type="arc" order="259.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis_2117" xlink:to="us-gaap_DebtInstrumentNameDomain_2118" />
    <link:definitionArc xlink:type="arc" order="261.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="sgly_VirginiaContemptJudgmentPayableAmount_2120" />
    <link:definitionArc xlink:type="arc" order="262.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="sgly_VirginiaFeeJudgmentPayableAmount_2121" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="sgly_CommitmentsandContingenciesDetailsTable_1644" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_CommitmentsandContingenciesDetailsTable_1644" xlink:to="srt_ProductOrServiceAxis_1660" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis_1660" xlink:to="srt_ProductsAndServicesDomain_1661" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_EscrowDeposit_1673" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_PaymentsForLegalSettlements_1669" />
    <link:definitionArc xlink:type="arc" order="24.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1681" />
    <link:definitionArc xlink:type="arc" order="26.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_PaymentsToAcquireLoansReceivable_1683" />
    <link:definitionArc xlink:type="arc" order="27.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LossContingenciesLineItems_1666" xlink:to="us-gaap_Revenues_1684" />
    <link:definitionArc xlink:type="arc" order="161.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TypeOfArrangementAxis_2001" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2002_default" />
    <link:definitionArc xlink:type="arc" order="170.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis_2010" xlink:to="us-gaap_SubsequentEventTypeDomain_2011_default" />
    <link:definitionArc xlink:type="arc" order="259.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis_2117" xlink:to="us-gaap_DebtInstrumentNameDomain_2118_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ProductOrServiceAxis_1660" xlink:to="srt_ProductsAndServicesDomain_1661_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandAndTwentyFiveWarrantMember" xlink:label="sgly_TwoThousandAndTwentyFiveWarrantMember_2057" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoThousandAndTwentyOneWarrantMember" xlink:label="sgly_TwoThousandAndTwentyOneWarrantMember_1396" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1929" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice_1399" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfWarrantsOutstandingAbstract" xlink:label="sgly_ScheduleOfWarrantsOutstandingAbstract_1393" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="us-gaap_ClassOfWarrantOrRightTable_1394" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_1395" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1397" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable_1398" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1929_default" />
    <link:definitionArc xlink:type="arc" order="212.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1929" xlink:to="sgly_TwoThousandAndTwentyFiveWarrantMember_2057" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1929" xlink:to="sgly_TwoThousandAndTwentyOneWarrantMember_1396" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1395" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1929" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1397" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice_1399" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1397" xlink:to="us-gaap_ClassOfWarrantOrRightTable_1394" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ClassOfWarrantOrRightTable_1394" xlink:to="us-gaap_ClassOfWarrantOrRightAxis_1395" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1397" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable_1398" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1395" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1929_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/EquityScheduleofWarrantsOutstandingandExercisableDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantMember" xlink:label="us-gaap_WarrantMember_1378" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_1377" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="us-gaap_ClassOfWarrantOrRightLineItems_1379" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_1380" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice_1381" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_1382" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable_1390" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentWeightedAverageExercisePriceExercisable" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentWeightedAverageExercisePriceExercisable_1391" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1928" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfWarrantsOutstandingAndExercisableAbstract" xlink:label="sgly_ScheduleOfWarrantsOutstandingAndExercisableAbstract_1375" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="us-gaap_ClassOfWarrantOrRightTable_1376" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice_1383" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_1384" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedWeightedAverageExercisePrice" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedWeightedAverageExercisePrice_1385" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations_1386" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpiredWeightedAverageExercisePrice" xlink:label="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpiredWeightedAverageExercisePrice_1387" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_1928_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_1928" xlink:to="us-gaap_WarrantMember_1378" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ClassOfWarrantOrRightTable_1376" xlink:to="us-gaap_ClassOfWarrantOrRightAxis_1377" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_1380" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice_1381" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_1382" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisable_1390" />
    <link:definitionArc xlink:type="arc" order="21.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentWeightedAverageExercisePriceExercisable_1391" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1377" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1928" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="us-gaap_ClassOfWarrantOrRightTable_1376" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantedWeightedAverageExercisePrice_1383" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_1384" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedWeightedAverageExercisePrice_1385" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations_1386" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems_1379" xlink:to="sgly_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpiredWeightedAverageExercisePrice_1387" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_1377" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_1928_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/NonControllingInterestScheduleofNonControllingInterestDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificShanghaiMember" xlink:label="sgly_TransPacificShanghaiMember_1413" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_BrilliantWarehouseMember" xlink:label="sgly_BrilliantWarehouseMember_1414" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfNonControllingInterestAbstract" xlink:label="sgly_ScheduleOfNonControllingInterestAbstract_1409" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemableNoncontrollingInterestByLegalEntityTable" xlink:label="us-gaap_RedeemableNoncontrollingInterestByLegalEntityTable_1410" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="srt_ConsolidatedEntitiesAxis_1411" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="srt_ConsolidatedEntitiesDomain_1412" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemableNoncontrollingInterestLineItems" xlink:label="us-gaap_RedeemableNoncontrollingInterestLineItems_1415" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest" xlink:label="us-gaap_MinorityInterest_1416" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="srt_ConsolidatedEntitiesDomain_1412_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain_1412" xlink:to="sgly_TransPacificShanghaiMember_1413" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain_1412" xlink:to="sgly_BrilliantWarehouseMember_1414" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RedeemableNoncontrollingInterestLineItems_1415" xlink:to="us-gaap_RedeemableNoncontrollingInterestByLegalEntityTable_1410" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_RedeemableNoncontrollingInterestByLegalEntityTable_1410" xlink:to="srt_ConsolidatedEntitiesAxis_1411" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis_1411" xlink:to="srt_ConsolidatedEntitiesDomain_1412" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RedeemableNoncontrollingInterestLineItems_1415" xlink:to="us-gaap_MinorityInterest_1416" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ConsolidatedEntitiesAxis_1411" xlink:to="srt_ConsolidatedEntitiesDomain_1412_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/ConcentrationsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplierConcentrationRiskMember" xlink:label="us-gaap_SupplierConcentrationRiskMember_1704" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_OneCustomerMember" xlink:label="sgly_OneCustomerMember_1707" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesRevenueNetMember" xlink:label="us-gaap_SalesRevenueNetMember_1709" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember" xlink:label="us-gaap_AccountsReceivableMember_1710" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableMember" xlink:label="us-gaap_AccountsPayableMember_1712" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_OneSuppliersMember" xlink:label="sgly_OneSuppliersMember_1715" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoSuppliersMember" xlink:label="sgly_TwoSuppliersMember_1716" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ThreeSuppliersMember" xlink:label="sgly_ThreeSuppliersMember_1717" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="us-gaap_CustomerConcentrationRiskMember_1703" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="us-gaap_ConcentrationRiskLineItems_1721" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="us-gaap_ConcentrationRiskPercentage1_1722" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="us-gaap_ConcentrationRiskTypeDomain_1935" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis" xlink:label="srt_MajorCustomersAxis_1705" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain" xlink:label="srt_NameOfMajorCustomerDomain_1706" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis_1708" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_1936" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1713" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRisksTypesNoConcentrationPercentageAbstract" xlink:label="us-gaap_ConcentrationRisksTypesNoConcentrationPercentageAbstract_1700" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ConcentrationsDetailsTable" xlink:label="sgly_ConcentrationsDetailsTable_1701" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_1702" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="us-gaap_ConcentrationRiskTypeDomain_1935_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain" xlink:label="srt_NameOfMajorCustomerDomain_1706_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_1936_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskTypeDomain_1935" xlink:to="us-gaap_SupplierConcentrationRiskMember_1704" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_NameOfMajorCustomerDomain_1706" xlink:to="sgly_OneCustomerMember_1707" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain_1936" xlink:to="us-gaap_SalesRevenueNetMember_1709" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain_1936" xlink:to="us-gaap_AccountsReceivableMember_1710" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain_1936" xlink:to="us-gaap_AccountsPayableMember_1712" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714" xlink:to="sgly_OneSuppliersMember_1715" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714" xlink:to="sgly_TwoSuppliersMember_1716" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714" xlink:to="sgly_ThreeSuppliersMember_1717" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskTypeDomain_1935" xlink:to="us-gaap_CustomerConcentrationRiskMember_1703" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskLineItems_1721" xlink:to="us-gaap_ConcentrationRiskPercentage1_1722" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ConcentrationRiskByTypeAxis_1702" xlink:to="us-gaap_ConcentrationRiskTypeDomain_1935" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ConcentrationsDetailsTable_1701" xlink:to="srt_MajorCustomersAxis_1705" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_MajorCustomersAxis_1705" xlink:to="srt_NameOfMajorCustomerDomain_1706" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ConcentrationsDetailsTable_1701" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis_1708" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis_1708" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_1936" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ConcentrationsDetailsTable_1701" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1713" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1713" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ConcentrationRiskLineItems_1721" xlink:to="sgly_ConcentrationsDetailsTable_1701" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ConcentrationsDetailsTable_1701" xlink:to="us-gaap_ConcentrationRiskByTypeAxis_1702" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ConcentrationRiskByTypeAxis_1702" xlink:to="us-gaap_ConcentrationRiskTypeDomain_1935_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_MajorCustomersAxis_1705" xlink:to="srt_NameOfMajorCustomerDomain_1706_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis_1708" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_1936_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1713" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1714_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ZhejiangJinbangFuelEnergyCoLtdMember" xlink:label="sgly_ZhejiangJinbangFuelEnergyCoLtdMember_1729" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_QinggangWangMember" xlink:label="sgly_QinggangWangMember_1730" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_MrWangQinggangMember" xlink:label="sgly_MrWangQinggangMember_1733" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShanghaiBaoyinIndustrialCoLtdMember" xlink:label="sgly_ShanghaiBaoyinIndustrialCoLtdMember_1728" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsAbstract" xlink:label="us-gaap_RelatedPartyTransactionsAbstract_1724" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1725" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1726" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="us-gaap_RelatedPartyTransactionLineItems_1734" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivables" xlink:label="us-gaap_OtherReceivables_1736" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage_1737" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities" xlink:label="us-gaap_OtherLiabilities_1738" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_1731" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="srt_EquityMethodInvesteeNameDomain_1732" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1727" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="srt_EquityMethodInvesteeNameDomain_1732_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1727_default" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1727" xlink:to="sgly_ZhejiangJinbangFuelEnergyCoLtdMember_1729" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1727" xlink:to="sgly_QinggangWangMember_1730" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_EquityMethodInvesteeNameDomain_1732" xlink:to="sgly_MrWangQinggangMember_1733" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1727" xlink:to="sgly_ShanghaiBaoyinIndustrialCoLtdMember_1728" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1734" xlink:to="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1725" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1725" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1726" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1734" xlink:to="us-gaap_OtherReceivables_1736" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1734" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage_1737" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1734" xlink:to="us-gaap_OtherLiabilities_1738" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1725" xlink:to="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_1731" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_1731" xlink:to="srt_EquityMethodInvesteeNameDomain_1732" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1726" xlink:to="us-gaap_RelatedPartyDomain_1727" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_1731" xlink:to="srt_EquityMethodInvesteeNameDomain_1732_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1726" xlink:to="us-gaap_RelatedPartyDomain_1727_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/DispositionofSubsidiariesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_NewEnergyTechLimitedMember" xlink:label="sgly_NewEnergyTechLimitedMember_1743" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="us-gaap_BusinessAcquisitionAxis_1742" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_DispositionOfSubsidiariesLineItems" xlink:label="sgly_DispositionOfSubsidiariesLineItems_1744" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1_1745" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationsAbstract" xlink:label="us-gaap_BusinessCombinationsAbstract_1740" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_DispositionofSubsidiariesDetailsTable" xlink:label="sgly_DispositionofSubsidiariesDetailsTable_1741" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_1937" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_1937_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain_1937" xlink:to="sgly_NewEnergyTechLimitedMember_1743" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_DispositionofSubsidiariesDetailsTable_1741" xlink:to="us-gaap_BusinessAcquisitionAxis_1742" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_DispositionOfSubsidiariesLineItems_1744" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1_1745" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgly_DispositionOfSubsidiariesLineItems_1744" xlink:to="sgly_DispositionofSubsidiariesDetailsTable_1741" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis_1742" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_1937" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis_1742" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_1937_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/SubsequentEventsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember_2060" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PreFundedWarrantsMember" xlink:label="sgly_PreFundedWarrantsMember_2064" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_1753" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantMember" xlink:label="us-gaap_WarrantMember_1992" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventsAbstract" xlink:label="us-gaap_SubsequentEventsAbstract_1747" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable" xlink:label="us-gaap_SubsequentEventTable_1748" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis_1990" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_1991" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PurchasePrice" xlink:label="sgly_PurchasePrice_1999" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CommonStockSharesIssuedToInvestors" xlink:label="sgly_CommonStockSharesIssuedToInvestors_2008" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_MinimumBidPrice" xlink:label="sgly_MinimumBidPrice_2014" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ConsecutiveBusinessDays" xlink:label="sgly_ConsecutiveBusinessDays_2017" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AggregateCommonStock" xlink:label="sgly_AggregateCommonStock_2019" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_2020" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GrossProceedsOfOffering" xlink:label="sgly_GrossProceedsOfOffering_2030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_2031" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding_2032" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_2033" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_2038" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CompliancePeriod" xlink:label="sgly_CompliancePeriod_2039" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_WarrantsExpireDate" xlink:label="sgly_WarrantsExpireDate_2051" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_2058" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_2059" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_2062" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_2063" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PurchasePriceOfEachShare" xlink:label="sgly_PurchasePriceOfEachShare_2065" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_1938" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_1752" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems" xlink:label="us-gaap_SubsequentEventLineItems_1754" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_1991_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_2063_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_1938_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1991" xlink:to="us-gaap_CommonStockMember_2060" />
    <link:definitionArc xlink:type="arc" order="218.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_2063" xlink:to="sgly_PreFundedWarrantsMember_2064" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain_1938" xlink:to="us-gaap_SubsequentEventMember_1753" />
    <link:definitionArc xlink:type="arc" order="219.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfWarrantOrRightDomain_2063" xlink:to="us-gaap_WarrantMember_1992" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_SubsequentEventTable_1748" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable_1748" xlink:to="us-gaap_StatementEquityComponentsAxis_1990" />
    <link:definitionArc xlink:type="arc" order="151.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis_1990" xlink:to="us-gaap_EquityComponentDomain_1991" />
    <link:definitionArc xlink:type="arc" order="158.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_PurchasePrice_1999" />
    <link:definitionArc xlink:type="arc" order="167.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_CommonStockSharesIssuedToInvestors_2008" />
    <link:definitionArc xlink:type="arc" order="173.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_MinimumBidPrice_2014" />
    <link:definitionArc xlink:type="arc" order="176.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_ConsecutiveBusinessDays_2017" />
    <link:definitionArc xlink:type="arc" order="178.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_AggregateCommonStock_2019" />
    <link:definitionArc xlink:type="arc" order="179.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_2020" />
    <link:definitionArc xlink:type="arc" order="187.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_GrossProceedsOfOffering_2030" />
    <link:definitionArc xlink:type="arc" order="188.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_2031" />
    <link:definitionArc xlink:type="arc" order="189.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_ClassOfWarrantOrRightOutstanding_2032" />
    <link:definitionArc xlink:type="arc" order="190.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering_2033" />
    <link:definitionArc xlink:type="arc" order="195.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_2038" />
    <link:definitionArc xlink:type="arc" order="196.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_CompliancePeriod_2039" />
    <link:definitionArc xlink:type="arc" order="206.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_WarrantsExpireDate_2051" />
    <link:definitionArc xlink:type="arc" order="213.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_2058" />
    <link:definitionArc xlink:type="arc" order="214.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="us-gaap_StockholdersEquityReverseStockSplit_2059" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable_1748" xlink:to="us-gaap_ClassOfWarrantOrRightAxis_2062" />
    <link:definitionArc xlink:type="arc" order="217.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_2062" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_2063" />
    <link:definitionArc xlink:type="arc" order="219.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems_1754" xlink:to="sgly_PurchasePriceOfEachShare_2065" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis_1752" xlink:to="us-gaap_SubsequentEventTypeDomain_1938" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable_1748" xlink:to="us-gaap_SubsequentEventTypeAxis_1752" />
    <link:definitionArc xlink:type="arc" order="151.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis_1990" xlink:to="us-gaap_EquityComponentDomain_1991_default" />
    <link:definitionArc xlink:type="arc" order="217.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ClassOfWarrantOrRightAxis_2062" xlink:to="us-gaap_ClassOfWarrantOrRightDomain_2063_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis_1752" xlink:to="us-gaap_SubsequentEventTypeDomain_1938_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxChargesMember" xlink:label="us-gaap_DeferredIncomeTaxChargesMember_1695" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_2049" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration" xlink:label="us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration_2125" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_1687" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="us-gaap_OperatingLossCarryforwardsTable_1688" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_1689" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1690" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US" xlink:label="country_US_1691" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_1692" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetAxis" xlink:label="us-gaap_RegulatoryAssetAxis_1693" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetDomain" xlink:label="us-gaap_RegulatoryAssetDomain_1694" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="us-gaap_OperatingLossCarryforwardsLineItems_1696" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="us-gaap_OperatingLossCarryforwards_1697" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_1698" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1690_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetDomain" xlink:label="us-gaap_RegulatoryAssetDomain_1694_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RegulatoryAssetDomain_1694" xlink:to="us-gaap_DeferredIncomeTaxChargesMember_1695" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems_1696" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_2049" />
    <link:definitionArc xlink:type="arc" order="266.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems_1696" xlink:to="us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration_2125" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems_1696" xlink:to="us-gaap_OperatingLossCarryforwardsTable_1688" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_OperatingLossCarryforwardsTable_1688" xlink:to="srt_StatementGeographicalAxis_1689" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_1689" xlink:to="srt_SegmentGeographicalDomain_1690" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1690" xlink:to="country_US_1691" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1690" xlink:to="country_CN_1692" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_OperatingLossCarryforwardsTable_1688" xlink:to="us-gaap_RegulatoryAssetAxis_1693" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RegulatoryAssetAxis_1693" xlink:to="us-gaap_RegulatoryAssetDomain_1694" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems_1696" xlink:to="us-gaap_OperatingLossCarryforwards_1697" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems_1696" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_1698" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_1689" xlink:to="srt_SegmentGeographicalDomain_1690_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RegulatoryAssetAxis_1693" xlink:to="us-gaap_RegulatoryAssetDomain_1694_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsScheduleofDuefromRelatedPartiesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ShanghaiBaoyinIndustrialCoLtdMember" xlink:label="sgly_ShanghaiBaoyinIndustrialCoLtdMember_1450" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ZhejiangJinbangFuelEnergyCoLtdMember" xlink:label="sgly_ZhejiangJinbangFuelEnergyCoLtdMember_1451" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember" xlink:label="us-gaap_RelatedPartyMember_1452" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1931" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1448" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1449" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="us-gaap_RelatedPartyTransactionLineItems_1453" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivables" xlink:label="us-gaap_OtherReceivables_1454" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfDueFromRelatedPartiesAbstract" xlink:label="sgly_ScheduleOfDueFromRelatedPartiesAbstract_1447" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_RelatedPartyImpairmentForCreditLosses" xlink:label="sgly_RelatedPartyImpairmentForCreditLosses_1455" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1931_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1931" xlink:to="sgly_ShanghaiBaoyinIndustrialCoLtdMember_1450" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1931" xlink:to="sgly_ZhejiangJinbangFuelEnergyCoLtdMember_1451" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1931" xlink:to="us-gaap_RelatedPartyMember_1452" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1449" xlink:to="us-gaap_RelatedPartyDomain_1931" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1453" xlink:to="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1448" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1448" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1449" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1453" xlink:to="us-gaap_OtherReceivables_1454" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems_1453" xlink:to="sgly_RelatedPartyImpairmentForCreditLosses_1455" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1449" xlink:to="us-gaap_RelatedPartyDomain_1931_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember" xlink:label="us-gaap_RelatedPartyMember_1460" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1932" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfAllowanceForCreditLossesLineItems" xlink:label="sgly_ScheduleOfAllowanceForCreditLossesLineItems_1461" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_RelatedPartyImpairmentForCreditLosses" xlink:label="sgly_RelatedPartyImpairmentForCreditLosses_1462" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_RelatedPartyImpairmentCreditLossWriteoff" xlink:label="sgly_RelatedPartyImpairmentCreditLossWriteoff_1463" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_RelatedPartImpairmentCreditLossExchangeRateEffect" xlink:label="sgly_RelatedPartImpairmentCreditLossExchangeRateEffect_1464" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfAllowanceForCreditLossesAbstract" xlink:label="sgly_ScheduleOfAllowanceForCreditLossesAbstract_1457" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetailsTable" xlink:label="sgly_RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetailsTable_1458" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1459" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1932_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1932" xlink:to="us-gaap_RelatedPartyMember_1460" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1459" xlink:to="us-gaap_RelatedPartyDomain_1932" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfAllowanceForCreditLossesLineItems_1461" xlink:to="sgly_RelatedPartyImpairmentForCreditLosses_1462" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfAllowanceForCreditLossesLineItems_1461" xlink:to="sgly_RelatedPartyImpairmentCreditLossWriteoff_1463" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfAllowanceForCreditLossesLineItems_1461" xlink:to="sgly_RelatedPartImpairmentCreditLossExchangeRateEffect_1464" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgly_ScheduleOfAllowanceForCreditLossesLineItems_1461" xlink:to="sgly_RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetailsTable_1458" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_RelatedPartyBalancesandTransactionsScheduleofAllowanceForCreditLossesDetailsTable_1458" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1459" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1459" xlink:to="us-gaap_RelatedPartyDomain_1932_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/DispositionofSubsidiariesScheduleofReconciliationofDispositionofSubsidiariesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_BrilliantWarehouseServiceIncMember" xlink:label="sgly_BrilliantWarehouseServiceIncMember_1470" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1933" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_2098" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfReconciliationOfDispositionOfSubsidiariesAbstract" xlink:label="sgly_ScheduleOfReconciliationOfDispositionOfSubsidiariesAbstract_1467" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_1468" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_DisposalGroupIncludingDiscontinuedOperationNetAssetsDisposedOf" xlink:label="sgly_DisposalGroupIncludingDiscontinuedOperationNetAssetsDisposedOf_1484" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_1485" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GainFromDisposalOfSubsidiaries" xlink:label="sgly_GainFromDisposalOfSubsidiaries_1486" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:label="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations_1487" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CashAndBankBalancesInSubsidiaryDisposedOf" xlink:label="sgly_CashAndBankBalancesInSubsidiaryDisposedOf_1488" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_1481" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInDiscontinuedOperations" xlink:label="us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_1489" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_1490" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_1491" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1469" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_DisposalGroupIncludingDiscontinuedOperationLoansFromThirdParties" xlink:label="sgly_DisposalGroupIncludingDiscontinuedOperationLoansFromThirdParties_1478" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities_1480" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CarryingAmountOfMajorClassesOfAssetsAbstract" xlink:label="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_1473" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_DisposalGroupIncludingDiscontinuedOperationRestrictedCash" xlink:label="sgly_DisposalGroupIncludingDiscontinuedOperationRestrictedCash_1474" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPrepaidAndOtherAssets" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationPrepaidAndOtherAssets_1475" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_1476" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract" xlink:label="sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract_1477" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CashOutflowArisingFromDisposalAbstract" xlink:label="sgly_CashOutflowArisingFromDisposalAbstract_1483" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1933_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1933" xlink:to="sgly_BrilliantWarehouseServiceIncMember_1470" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1469" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1933" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_2098" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_1468" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="sgly_DisposalGroupIncludingDiscontinuedOperationNetAssetsDisposedOf_1484" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_1485" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="sgly_GainFromDisposalOfSubsidiaries_1486" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations_1487" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="sgly_CashAndBankBalancesInSubsidiaryDisposedOf_1488" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract_1477" xlink:to="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_1481" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CashOutflowArisingFromDisposalAbstract_1483" xlink:to="us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_1489" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_1490" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="us-gaap_NetIncomeLoss_1491" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_1468" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1469" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract_1477" xlink:to="sgly_DisposalGroupIncludingDiscontinuedOperationLoansFromThirdParties_1478" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract_1477" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities_1480" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_1473" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" xlink:to="sgly_DisposalGroupIncludingDiscontinuedOperationRestrictedCash_1474" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationPrepaidAndOtherAssets_1475" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_CarryingAmountOfMajorClassesOfAssetsAbstract_1472" xlink:to="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_1476" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="sgly_CarryingAmountOfMajorClassesOfLiabilitiesAbstract_1477" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1471" xlink:to="sgly_CashOutflowArisingFromDisposalAbstract_1483" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1469" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1933_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/ConsolidatedStatementsofChangesInEquity" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember_1094" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="us-gaap_AdditionalPaidInCapitalMember_1095" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember_1096" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:label="us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_1097" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ParentMember" xlink:label="us-gaap_ParentMember_1098" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="us-gaap_NoncontrollingInterestMember_1099" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember" xlink:label="us-gaap_PreferredStockMember_1947" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis_1092" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueOther" xlink:label="us-gaap_StockIssuedDuringPeriodValueOther_1106" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="us-gaap_StockIssuedDuringPeriodSharesOther_1107" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_1108" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation" xlink:label="us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_1109" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss_1110" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1111" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesOutstanding" xlink:label="us-gaap_SharesOutstanding_1112" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_1090" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_1091" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_1100" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_1101" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_1104" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1105" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_1100_default" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_CommonStockMember_1094" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_AdditionalPaidInCapitalMember_1095" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_RetainedEarningsMember_1096" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_1097" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_ParentMember_1098" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_NoncontrollingInterestMember_1099" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain_1100" xlink:to="us-gaap_PreferredStockMember_1947" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable_1091" xlink:to="us-gaap_StatementEquityComponentsAxis_1092" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StockIssuedDuringPeriodValueOther_1106" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StockIssuedDuringPeriodSharesOther_1107" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_1108" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_1109" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_ProfitLoss_1110" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1111" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_SharesOutstanding_1112" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StatementTable_1091" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis_1092" xlink:to="us-gaap_EquityComponentDomain_1100" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues_1104" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1101" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_1105" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis_1092" xlink:to="us-gaap_EquityComponentDomain_1100_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/OrganizationandNatureofBusinessDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SecuritiesPurchaseAgreementMember" xlink:label="sgly_SecuritiesPurchaseAgreementMember_1954" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="srt_RangeMember_1964" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember_1965" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_1966" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_FirstPurchaseAgreementMember" xlink:label="sgly_FirstPurchaseAgreementMember_1967" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SecondPurchaseAgreementMember" xlink:label="sgly_SecondPurchaseAgreementMember_1968" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SecondSecuritiesPurchaseAgreementMember" xlink:label="sgly_SecondSecuritiesPurchaseAgreementMember_1971" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_NewEnergyTechLimitedMember" xlink:label="sgly_NewEnergyTechLimitedMember_1497" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_1951" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_1955" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_1956" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_OfferingPricePerShare" xlink:label="sgly_OfferingPricePerShare_1957" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_1958" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_1960" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_1963" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding_1969" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockPricePerShare" xlink:label="us-gaap_SaleOfStockPricePerShare_1970" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_2124" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_1496" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="us-gaap_BusinessAcquisitionLineItems_1498" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1_1499" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss_1500" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_1501" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Cash" xlink:label="us-gaap_Cash_1502" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_1949" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_1950" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_1952" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_1493" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_OrganizationandNatureofBusinessDetailsTable" xlink:label="sgly_OrganizationandNatureofBusinessDetailsTable_1494" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="us-gaap_BusinessAcquisitionAxis_1495" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_NumberOfUnitShares" xlink:label="sgly_NumberOfUnitShares_2052" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="srt_RangeMember_1964_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_1496_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_1950_default" />
    <link:definitionArc xlink:type="arc" order="115.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis_1952" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" />
    <link:definitionArc xlink:type="arc" order="116.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" xlink:to="sgly_SecuritiesPurchaseAgreementMember_1954" />
    <link:definitionArc xlink:type="arc" order="125.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis_1963" xlink:to="srt_RangeMember_1964" />
    <link:definitionArc xlink:type="arc" order="126.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember_1964" xlink:to="srt_MinimumMember_1965" />
    <link:definitionArc xlink:type="arc" order="127.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember_1964" xlink:to="srt_MaximumMember_1966" />
    <link:definitionArc xlink:type="arc" order="128.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" xlink:to="sgly_FirstPurchaseAgreementMember_1967" />
    <link:definitionArc xlink:type="arc" order="129.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" xlink:to="sgly_SecondPurchaseAgreementMember_1968" />
    <link:definitionArc xlink:type="arc" order="132.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953" xlink:to="sgly_SecondSecuritiesPurchaseAgreementMember_1971" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain_1496" xlink:to="sgly_NewEnergyTechLimitedMember_1497" />
    <link:definitionArc xlink:type="arc" order="113.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain_1950" xlink:to="us-gaap_SubsequentEventMember_1951" />
    <link:definitionArc xlink:type="arc" order="117.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_1955" />
    <link:definitionArc xlink:type="arc" order="118.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_1956" />
    <link:definitionArc xlink:type="arc" order="119.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="sgly_OfferingPricePerShare_1957" />
    <link:definitionArc xlink:type="arc" order="120.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering_1958" />
    <link:definitionArc xlink:type="arc" order="122.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_1960" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_OrganizationandNatureofBusinessDetailsTable_1494" xlink:to="srt_RangeAxis_1963" />
    <link:definitionArc xlink:type="arc" order="130.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_ClassOfWarrantOrRightOutstanding_1969" />
    <link:definitionArc xlink:type="arc" order="131.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_SaleOfStockPricePerShare_1970" />
    <link:definitionArc xlink:type="arc" order="265.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_StockholdersEquityReverseStockSplit_2124" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis_1495" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_1496" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1_1499" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_ProfitLoss_1500" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_1501" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="us-gaap_Cash_1502" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_OrganizationandNatureofBusinessDetailsTable_1494" xlink:to="us-gaap_SubsequentEventTypeAxis_1949" />
    <link:definitionArc xlink:type="arc" order="112.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis_1949" xlink:to="us-gaap_SubsequentEventTypeDomain_1950" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_OrganizationandNatureofBusinessDetailsTable_1494" xlink:to="us-gaap_TypeOfArrangementAxis_1952" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="sgly_OrganizationandNatureofBusinessDetailsTable_1494" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_OrganizationandNatureofBusinessDetailsTable_1494" xlink:to="us-gaap_BusinessAcquisitionAxis_1495" />
    <link:definitionArc xlink:type="arc" order="207.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems_1498" xlink:to="sgly_NumberOfUnitShares_2052" />
    <link:definitionArc xlink:type="arc" order="115.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TypeOfArrangementAxis_1952" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_1953_default" />
    <link:definitionArc xlink:type="arc" order="125.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_RangeAxis_1963" xlink:to="srt_RangeMember_1964_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis_1495" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_1496_default" />
    <link:definitionArc xlink:type="arc" order="112.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis_1949" xlink:to="us-gaap_SubsequentEventTypeDomain_1950_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/ConsolidatedBalanceSheets" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember" xlink:label="us-gaap_RelatedPartyMember_1006" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLongTermInvestments" xlink:label="us-gaap_OtherLongTermInvestments_1018" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrent" xlink:label="us-gaap_AssetsNoncurrent_1019" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets_1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract_1021" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansPayableCurrent" xlink:label="us-gaap_LoansPayableCurrent_1022" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableTradeCurrent" xlink:label="us-gaap_AccountsPayableTradeCurrent_1024" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_1025" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesPayableCurrent" xlink:label="us-gaap_TaxesPayableCurrent_1026" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="us-gaap_OtherLiabilitiesCurrent_1027" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtCurrent" xlink:label="us-gaap_ConvertibleDebtCurrent_1028" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ClassActionSettlement" xlink:label="sgly_ClassActionSettlement_1029" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="us-gaap_AccruedLiabilitiesAndOtherLiabilities_1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent_1031" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="us-gaap_LiabilitiesNoncurrentAbstract_1032" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermLoansPayable" xlink:label="us-gaap_LongTermLoansPayable_1033" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_1042" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1043" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_1044" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest" xlink:label="us-gaap_MinorityInterest_1045" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1046" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_1047" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_1017" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_1034" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="us-gaap_LiabilitiesNoncurrent_1035" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_1036" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="us-gaap_CommitmentsAndContingencies_1037" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract_1038" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue_1039" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_1040" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital_1041" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_1002" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_1003" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1004" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1005" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_1007" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="us-gaap_AssetsCurrentAbstract_1008" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Cash" xlink:label="us-gaap_Cash_1009" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_1941" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashCurrent" xlink:label="us-gaap_RestrictedCashCurrent_1010" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableNetCurrent" xlink:label="us-gaap_NotesAndLoansReceivableNetCurrent_1011" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="us-gaap_AccountsReceivableNetCurrent_1012" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdvancesOnInventoryPurchases" xlink:label="us-gaap_AdvancesOnInventoryPurchases_1013" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent_1015" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrentAbstract" xlink:label="us-gaap_AssetsNoncurrentAbstract_1016" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_1005_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain_1005" xlink:to="us-gaap_RelatedPartyMember_1006" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsNoncurrentAbstract_1016" xlink:to="us-gaap_OtherLongTermInvestments_1018" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsNoncurrentAbstract_1016" xlink:to="us-gaap_AssetsNoncurrent_1019" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_Assets_1020" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_LiabilitiesCurrentAbstract_1021" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_LoansPayableCurrent_1022" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_AccountsPayableTradeCurrent_1024" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_1025" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_TaxesPayableCurrent_1026" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_OtherLiabilitiesCurrent_1027" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_ConvertibleDebtCurrent_1028" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="sgly_ClassActionSettlement_1029" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_AccruedLiabilitiesAndOtherLiabilities_1030" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract_1021" xlink:to="us-gaap_LiabilitiesCurrent_1031" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_LiabilitiesNoncurrentAbstract_1032" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesNoncurrentAbstract_1032" xlink:to="us-gaap_LongTermLoansPayable_1033" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StockholdersEquityAbstract_1038" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_1042" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StockholdersEquityAbstract_1038" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1043" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_StockholdersEquity_1044" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_MinorityInterest_1045" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1046" />
    <link:definitionArc xlink:type="arc" order="21.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_1047" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsNoncurrentAbstract_1016" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_1017" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesNoncurrentAbstract_1032" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_1034" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesNoncurrentAbstract_1032" xlink:to="us-gaap_LiabilitiesNoncurrent_1035" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_Liabilities_1036" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_CommitmentsAndContingencies_1037" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_StockholdersEquityAbstract_1038" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StockholdersEquityAbstract_1038" xlink:to="us-gaap_PreferredStockValue_1039" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StockholdersEquityAbstract_1038" xlink:to="us-gaap_CommonStockValue_1040" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StockholdersEquityAbstract_1038" xlink:to="us-gaap_AdditionalPaidInCapital_1041" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_StatementTable_1003" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable_1003" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1004" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1004" xlink:to="us-gaap_RelatedPartyDomain_1005" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_AssetsCurrentAbstract_1008" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_Cash_1009" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_1941" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_RestrictedCashCurrent_1010" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_NotesAndLoansReceivableNetCurrent_1011" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_AccountsReceivableNetCurrent_1012" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_AdvancesOnInventoryPurchases_1013" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract_1008" xlink:to="us-gaap_AssetsCurrent_1015" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems_1007" xlink:to="us-gaap_AssetsNoncurrentAbstract_1016" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1004" xlink:to="us-gaap_RelatedPartyDomain_1005_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofPreTaxIncomeDisaggregatedDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_2093" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems" xlink:label="sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems_2095" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US" xlink:label="country_US_2096" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_2086" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_2087" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_2088" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2089" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTable_2090" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_2091" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_2092" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_2092_default" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_2092" xlink:to="country_CN_2093" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_2092" xlink:to="country_US_2096" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems_2095" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_2087" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems_2095" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_2088" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems_2095" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2089" />
    <link:definitionArc xlink:type="arc" order="236.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgly_ScheduleOfPreTaxIncomeDisaggregatedLineItems_2095" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTable_2090" />
    <link:definitionArc xlink:type="arc" order="237.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationTable_2090" xlink:to="srt_StatementGeographicalAxis_2091" />
    <link:definitionArc xlink:type="arc" order="238.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_2091" xlink:to="srt_SegmentGeographicalDomain_2092" />
    <link:definitionArc xlink:type="arc" order="238.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_2091" xlink:to="srt_SegmentGeographicalDomain_2092_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/OrganizationandNatureofBusinessScheduleofSubsidiariesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsTwoMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsTwoMember_1282" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIMember_1283" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIOneMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIOneMember_1284" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVITwoMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVITwoMember_1285" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GorgeousTradingLtdGorgeousTradingMember" xlink:label="sgly_GorgeousTradingLtdGorgeousTradingMember_1298" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GorgeousTradingLtdGorgeousTradingOneMember" xlink:label="sgly_GorgeousTradingLtdGorgeousTradingOneMember_1299" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GorgeousTradingLtdGorgeousTradingTwoMember" xlink:label="sgly_GorgeousTradingLtdGorgeousTradingTwoMember_1300" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SGShippingRiskSolutionIncSGSRMember" xlink:label="sgly_SGShippingRiskSolutionIncSGSRMember_1301" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingNewYorkIncSGSNYMember" xlink:label="sgly_SinoGlobalShippingNewYorkIncSGSNYMember_1286" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificShippingLtdTransPacificBeijingOneMember" xlink:label="sgly_TransPacificShippingLtdTransPacificBeijingOneMember_1293" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificShippingLtdTransPacificBeijingTwoMember" xlink:label="sgly_TransPacificShippingLtdTransPacificBeijingTwoMember_1294" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiMember" xlink:label="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiMember_1295" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiOneMember" xlink:label="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiOneMember_1296" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiTwoMember" xlink:label="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiTwoMember_1297" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SGShippingRiskSolutionIncSGSROneMember" xlink:label="sgly_SGShippingRiskSolutionIncSGSROneMember_1302" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SGShippingRiskSolutionIncSGSRTwoMember" xlink:label="sgly_SGShippingRiskSolutionIncSGSRTwoMember_1303" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsMember_1280" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsOneMember" xlink:label="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsOneMember_1281" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingNewYorkIncSGSNYOneMember" xlink:label="sgly_SinoGlobalShippingNewYorkIncSGSNYOneMember_1287" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingNewYorkIncSGSNYTwoMember" xlink:label="sgly_SinoGlobalShippingNewYorkIncSGSNYTwoMember_1288" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingHKLtdSGSHKMember" xlink:label="sgly_SinoGlobalShippingHKLtdSGSHKMember_1289" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingHKLtdSGSHKOneMember" xlink:label="sgly_SinoGlobalShippingHKLtdSGSHKOneMember_1290" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SinoGlobalShippingHKLtdSGSHKTwoMember" xlink:label="sgly_SinoGlobalShippingHKLtdSGSHKTwoMember_1291" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TransPacificShippingLtdTransPacificBeijingMember" xlink:label="sgly_TransPacificShippingLtdTransPacificBeijingMember_1292" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SingularityShenzhenTechnologyLtdMember" xlink:label="sgly_SingularityShenzhenTechnologyLtdMember_1304" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SingularityShenzhenTechnologyLtdOneMember" xlink:label="sgly_SingularityShenzhenTechnologyLtdOneMember_1305" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SingularityShenzhenTechnologyLtdTwoMember" xlink:label="sgly_SingularityShenzhenTechnologyLtdTwoMember_1306" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SingularityFutureTechnologyVirginiaIncMember" xlink:label="sgly_SingularityFutureTechnologyVirginiaIncMember_1972" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain" xlink:label="srt_OwnershipDomain_1925" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfSubsidiariesAbstract" xlink:label="sgly_ScheduleOfSubsidiariesAbstract_1277" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable" xlink:label="us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_1278" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis" xlink:label="srt_OwnershipAxis_1279" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeLineItems" xlink:label="us-gaap_SubsidiaryOrEquityMethodInvesteeLineItems_1307" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipBusinessPurpose" xlink:label="us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipBusinessPurpose_1308" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByParent_1309" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain" xlink:label="srt_OwnershipDomain_1925_default" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsTwoMember_1282" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIMember_1283" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVIOneMember_1284" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdBVITwoMember_1285" />
    <link:definitionArc xlink:type="arc" order="28.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_GorgeousTradingLtdGorgeousTradingMember_1298" />
    <link:definitionArc xlink:type="arc" order="29.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_GorgeousTradingLtdGorgeousTradingOneMember_1299" />
    <link:definitionArc xlink:type="arc" order="30.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_GorgeousTradingLtdGorgeousTradingTwoMember_1300" />
    <link:definitionArc xlink:type="arc" order="31.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SGShippingRiskSolutionIncSGSRMember_1301" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingNewYorkIncSGSNYMember_1286" />
    <link:definitionArc xlink:type="arc" order="23.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificShippingLtdTransPacificBeijingOneMember_1293" />
    <link:definitionArc xlink:type="arc" order="24.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificShippingLtdTransPacificBeijingTwoMember_1294" />
    <link:definitionArc xlink:type="arc" order="25.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiMember_1295" />
    <link:definitionArc xlink:type="arc" order="26.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiOneMember_1296" />
    <link:definitionArc xlink:type="arc" order="27.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificLogisticShanghaiLtdTransPacificShanghaiTwoMember_1297" />
    <link:definitionArc xlink:type="arc" order="32.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SGShippingRiskSolutionIncSGSROneMember_1302" />
    <link:definitionArc xlink:type="arc" order="33.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SGShippingRiskSolutionIncSGSRTwoMember_1303" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsMember_1280" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_ArtificialIntelligenceRegenerationTechnologyCoLtdCaymanIslandsOneMember_1281" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingNewYorkIncSGSNYOneMember_1287" />
    <link:definitionArc xlink:type="arc" order="18.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingNewYorkIncSGSNYTwoMember_1288" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingHKLtdSGSHKMember_1289" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingHKLtdSGSHKOneMember_1290" />
    <link:definitionArc xlink:type="arc" order="21.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SinoGlobalShippingHKLtdSGSHKTwoMember_1291" />
    <link:definitionArc xlink:type="arc" order="22.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_TransPacificShippingLtdTransPacificBeijingMember_1292" />
    <link:definitionArc xlink:type="arc" order="34.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SingularityShenzhenTechnologyLtdMember_1304" />
    <link:definitionArc xlink:type="arc" order="35.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SingularityShenzhenTechnologyLtdOneMember_1305" />
    <link:definitionArc xlink:type="arc" order="36.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SingularityShenzhenTechnologyLtdTwoMember_1306" />
    <link:definitionArc xlink:type="arc" order="133.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain_1925" xlink:to="sgly_SingularityFutureTechnologyVirginiaIncMember_1972" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_OwnershipAxis_1279" xlink:to="srt_OwnershipDomain_1925" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeLineItems_1307" xlink:to="us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_1278" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipTable_1278" xlink:to="srt_OwnershipAxis_1279" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeLineItems_1307" xlink:to="us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipBusinessPurpose_1308" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeLineItems_1307" xlink:to="us-gaap_MinorityInterestOwnershipPercentageByParent_1309" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_OwnershipAxis_1279" xlink:to="srt_OwnershipDomain_1925_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofDisaggregatedRevenueStreamsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_FreightLogisticServicesMember" xlink:label="sgly_FreightLogisticServicesMember_1327" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_1926" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="us-gaap_DisaggregationOfRevenueLineItems_1328" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_1329" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfDisaggregatedRevenueStreamsAbstract" xlink:label="sgly_ScheduleOfDisaggregatedRevenueStreamsAbstract_1324" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="us-gaap_DisaggregationOfRevenueTable_1325" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis_1326" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_1926_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain_1926" xlink:to="sgly_FreightLogisticServicesMember_1327" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis_1326" xlink:to="srt_ProductsAndServicesDomain_1926" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems_1328" xlink:to="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_1329" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DisaggregationOfRevenueLineItems_1328" xlink:to="us-gaap_DisaggregationOfRevenueTable_1325" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DisaggregationOfRevenueTable_1325" xlink:to="srt_ProductOrServiceAxis_1326" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ProductOrServiceAxis_1326" xlink:to="srt_ProductsAndServicesDomain_1926_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1927" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfRevenuesByGeographicLocationsAbstract" xlink:label="sgly_ScheduleOfRevenuesByGeographicLocationsAbstract_1331" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_1334" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems" xlink:label="us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_1335" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues_1336" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetailsTable" xlink:label="sgly_SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetailsTable_1332" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_1333" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1927_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_1333" xlink:to="srt_SegmentGeographicalDomain_1927" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1927" xlink:to="country_CN_1334" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_1335" xlink:to="us-gaap_Revenues_1336" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_1335" xlink:to="sgly_SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetailsTable_1332" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesScheduleofRevenuesbyGeographicLocationsDetailsTable_1332" xlink:to="srt_StatementGeographicalAxis_1333" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_1333" xlink:to="srt_SegmentGeographicalDomain_1927_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2036" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SettlementAgreementMember" xlink:label="sgly_SettlementAgreementMember_2037" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AverageExchangeRatesMember" xlink:label="sgly_AverageExchangeRatesMember_1512" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_EastWestBankMember" xlink:label="sgly_EastWestBankMember_1527" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="srt_RangeMember_1507" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember_1508" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_1509" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Cash" xlink:label="us-gaap_Cash_1530" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashUninsuredAmount" xlink:label="us-gaap_CashUninsuredAmount_1531" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashFDICInsuredAmount" xlink:label="us-gaap_CashFDICInsuredAmount_1532" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1514" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_1515" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US" xlink:label="country_US_1516" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_DJ" xlink:label="country_DJ_1517" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntercompanyForeignCurrencyBalanceNameDomain" xlink:label="us-gaap_IntercompanyForeignCurrencyBalanceNameDomain_1511" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_2035" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="us-gaap_NumberOfOperatingSegments_2066" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_NumberOfContractedVolume" xlink:label="sgly_NumberOfContractedVolume_2067" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CurrencyAxis" xlink:label="srt_CurrencyAxis_1521" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AllCurrenciesDomain" xlink:label="currency_AllCurrenciesDomain_1522" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_USD" xlink:label="currency_USD_1523" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_1513" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyExchangeRateTranslation1" xlink:label="us-gaap_ForeignCurrencyExchangeRateTranslation1_1529" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashCurrent" xlink:label="us-gaap_RestrictedCashCurrent_1533" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashEquivalents" xlink:label="us-gaap_RestrictedCashEquivalents_1534" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCash" xlink:label="us-gaap_RestrictedCash_1535" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_EducationSurchargesRatePercentage" xlink:label="sgly_EducationSurchargesRatePercentage_1543" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription" xlink:label="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_1544" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration" xlink:label="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_1545" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments" xlink:label="us-gaap_NumberOfReportableSegments_1546" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_CNY" xlink:label="currency_CNY_1524" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="us-gaap_LineOfCreditFacilityAxis_1525" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_1526" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubordinatedBorrowingInterestRate" xlink:label="us-gaap_SubordinatedBorrowingInterestRate_1538" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilityForUncertainTaxPositionsCurrent" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent_1539" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PercentageOfIncomeTax" xlink:label="sgly_PercentageOfIncomeTax_1540" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ValueAddedTaxPercentage" xlink:label="sgly_ValueAddedTaxPercentage_1541" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ConstructionTaxesRatePercentage" xlink:label="sgly_ConstructionTaxesRatePercentage_1542" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PercentageOfRevenue" xlink:label="sgly_PercentageOfRevenue_1976" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="us-gaap_AccountingPoliciesAbstract_1504" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SummaryofSignificantAccountingPoliciesDetailsTable" xlink:label="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_1506" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntercompanyForeignCurrencyBalanceByDescriptionAxis" xlink:label="us-gaap_IntercompanyForeignCurrencyBalanceByDescriptionAxis_1510" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2036_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="srt_RangeMember_1507_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1514_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntercompanyForeignCurrencyBalanceNameDomain" xlink:label="us-gaap_IntercompanyForeignCurrencyBalanceNameDomain_1511_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AllCurrenciesDomain" xlink:label="currency_AllCurrenciesDomain_1522_default" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_1526_default" />
    <link:definitionArc xlink:type="arc" order="193.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis_2035" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2036" />
    <link:definitionArc xlink:type="arc" order="194.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2036" xlink:to="sgly_SettlementAgreementMember_2037" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IntercompanyForeignCurrencyBalanceNameDomain_1511" xlink:to="sgly_AverageExchangeRatesMember_1512" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain_1526" xlink:to="sgly_EastWestBankMember_1527" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis_1506" xlink:to="srt_RangeMember_1507" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember_1507" xlink:to="srt_MinimumMember_1508" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember_1507" xlink:to="srt_MaximumMember_1509" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_Cash_1530" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_CashUninsuredAmount_1531" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_CashFDICInsuredAmount_1532" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_1513" xlink:to="srt_SegmentGeographicalDomain_1514" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1514" xlink:to="country_CN_1515" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1514" xlink:to="country_US_1516" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1514" xlink:to="country_DJ_1517" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IntercompanyForeignCurrencyBalanceByDescriptionAxis_1510" xlink:to="us-gaap_IntercompanyForeignCurrencyBalanceNameDomain_1511" />
    <link:definitionArc xlink:type="arc" order="17.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="us-gaap_TypeOfArrangementAxis_2035" />
    <link:definitionArc xlink:type="arc" order="220.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_NumberOfOperatingSegments_2066" />
    <link:definitionArc xlink:type="arc" order="221.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_NumberOfContractedVolume_2067" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="srt_CurrencyAxis_1521" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_CurrencyAxis_1521" xlink:to="currency_AllCurrenciesDomain_1522" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="currency_AllCurrenciesDomain_1522" xlink:to="currency_USD_1523" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="srt_StatementGeographicalAxis_1513" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_ForeignCurrencyExchangeRateTranslation1_1529" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_RestrictedCashCurrent_1533" />
    <link:definitionArc xlink:type="arc" order="15.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_RestrictedCashEquivalents_1534" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_RestrictedCash_1535" />
    <link:definitionArc xlink:type="arc" order="24.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_EducationSurchargesRatePercentage_1543" />
    <link:definitionArc xlink:type="arc" order="25.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_1544" />
    <link:definitionArc xlink:type="arc" order="26.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_1545" />
    <link:definitionArc xlink:type="arc" order="27.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_NumberOfReportableSegments_1546" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="currency_AllCurrenciesDomain_1522" xlink:to="currency_CNY_1524" />
    <link:definitionArc xlink:type="arc" order="16.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="us-gaap_LineOfCreditFacilityAxis_1525" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LineOfCreditFacilityAxis_1525" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain_1526" />
    <link:definitionArc xlink:type="arc" order="19.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_SubordinatedBorrowingInterestRate_1538" />
    <link:definitionArc xlink:type="arc" order="20.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="us-gaap_LiabilityForUncertainTaxPositionsCurrent_1539" />
    <link:definitionArc xlink:type="arc" order="21.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_PercentageOfIncomeTax_1540" />
    <link:definitionArc xlink:type="arc" order="22.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_ValueAddedTaxPercentage_1541" />
    <link:definitionArc xlink:type="arc" order="23.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_ConstructionTaxesRatePercentage_1542" />
    <link:definitionArc xlink:type="arc" order="137.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_PercentageOfRevenue_1976" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_1528" xlink:to="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="srt_RangeAxis_1506" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesDetailsTable_1505" xlink:to="us-gaap_IntercompanyForeignCurrencyBalanceByDescriptionAxis_1510" />
    <link:definitionArc xlink:type="arc" order="193.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TypeOfArrangementAxis_2035" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2036_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_RangeAxis_1506" xlink:to="srt_RangeMember_1507_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_1513" xlink:to="srt_SegmentGeographicalDomain_1514_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IntercompanyForeignCurrencyBalanceByDescriptionAxis_1510" xlink:to="us-gaap_IntercompanyForeignCurrencyBalanceNameDomain_1511_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_CurrencyAxis_1521" xlink:to="currency_AllCurrenciesDomain_1522_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_LineOfCreditFacilityAxis_1525" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain_1526_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_LessThanOneYearMember" xlink:label="sgly_LessThanOneYearMember_1315" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_OneToTwoYearsMember" xlink:label="sgly_OneToTwoYearsMember_1316" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_TwoToThreeYearsMember" xlink:label="sgly_TwoToThreeYearsMember_1317" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_GreaterThanThreeYearsMember" xlink:label="sgly_GreaterThanThreeYearsMember_1318" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_1319" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNet" xlink:label="us-gaap_AccountsReceivableNet_1320" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfAgingAnalysisOfAccountsReceivableAndAllowanceForCreditLossesAbstract" xlink:label="sgly_ScheduleOfAgingAnalysisOfAccountsReceivableAndAllowanceForCreditLossesAbstract_1311" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetailsTable" xlink:label="sgly_SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetailsTable_1312" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_1313" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_PercentageOfCurrentExpectedCreditLoss" xlink:label="sgly_PercentageOfCurrentExpectedCreditLoss_1321" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_1322" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" xlink:to="sgly_LessThanOneYearMember_1315" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" xlink:to="sgly_OneToTwoYearsMember_1316" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" xlink:to="sgly_TwoToThreeYearsMember_1317" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" xlink:to="sgly_GreaterThanThreeYearsMember_1318" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_1319" xlink:to="us-gaap_AccountsReceivableNet_1320" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_1319" xlink:to="sgly_SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetailsTable_1312" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_SummaryofSignificantAccountingPoliciesScheduleofAgingAnalysisofAccountsReceivableandAllowanceforCreditLossesDetailsTable_1312" xlink:to="us-gaap_FinancingReceivablesPeriodPastDueAxis_1313" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueAxis_1313" xlink:to="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_1319" xlink:to="sgly_PercentageOfCurrentExpectedCreditLoss_1321" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_1319" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivable_1322" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueAxis_1313" xlink:to="us-gaap_FinancingReceivablesPeriodPastDueDomain_1314_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/LoansfromThirdPartiesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_LoansFromThirdPartiesMember" xlink:label="sgly_LoansFromThirdPartiesMember_1563" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="us-gaap_DebtDisclosureAbstract_1559" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating" xlink:label="us-gaap_InterestExpenseNonoperating_1568" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_LoansfromThirdPartiesDetailsTable" xlink:label="sgly_LoansfromThirdPartiesDetailsTable_1560" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis_1561" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1562" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems_1564" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansPayable" xlink:label="us-gaap_LoansPayable_1565" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtWeightedAverageInterestRate" xlink:label="us-gaap_DebtWeightedAverageInterestRate_1566" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_WeightedAverageMaturity" xlink:label="sgly_WeightedAverageMaturity_1567" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_1562_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain_1562" xlink:to="sgly_LoansFromThirdPartiesMember_1563" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1564" xlink:to="us-gaap_InterestExpenseNonoperating_1568" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems_1564" xlink:to="sgly_LoansfromThirdPartiesDetailsTable_1560" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_LoansfromThirdPartiesDetailsTable_1560" xlink:to="us-gaap_DebtInstrumentAxis_1561" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis_1561" xlink:to="us-gaap_DebtInstrumentNameDomain_1562" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1564" xlink:to="us-gaap_LoansPayable_1565" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1564" xlink:to="us-gaap_DebtWeightedAverageInterestRate_1566" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems_1564" xlink:to="sgly_WeightedAverageMaturity_1567" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis_1561" xlink:to="us-gaap_DebtInstrumentNameDomain_1562_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/AdvancestoSuppliersScheduleofAdvancestoSuppliersDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_CommodityTradingMember" xlink:label="sgly_CommodityTradingMember_1345" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_FreightFeesMember" xlink:label="sgly_FreightFeesMember_1346" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfAdvancesToSuppliersAbstract" xlink:label="sgly_ScheduleOfAdvancesToSuppliersAbstract_1341" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AdvancestoSuppliersScheduleofAdvancestoSuppliersDetailsTable" xlink:label="sgly_AdvancestoSuppliersScheduleofAdvancestoSuppliersDetailsTable_1342" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1343" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_AdvancesToSuppliersLineItems" xlink:label="sgly_AdvancesToSuppliersLineItems_1347" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdvancesOnInventoryPurchases" xlink:label="us-gaap_AdvancesOnInventoryPurchases_1348" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain" xlink:label="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344" xlink:to="sgly_CommodityTradingMember_1345" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344" xlink:to="sgly_FreightFeesMember_1346" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgly_AdvancesToSuppliersLineItems_1347" xlink:to="sgly_AdvancestoSuppliersScheduleofAdvancestoSuppliersDetailsTable_1342" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_AdvancestoSuppliersScheduleofAdvancestoSuppliersDetailsTable_1342" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1343" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1343" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_AdvancesToSuppliersLineItems_1347" xlink:to="us-gaap_AdvancesOnInventoryPurchases_1348" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_1343" xlink:to="us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_1344_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofIncomeTaxExpensesDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfIncomeTaxExpensesAbstract" xlink:label="sgly_ScheduleOfIncomeTaxExpensesAbstract_1418" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfIncomeTaxExpensesTable" xlink:label="sgly_ScheduleOfIncomeTaxExpensesTable_1419" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_1420" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1421" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US" xlink:label="country_US_1422" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_1423" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfIncomeTaxExpensesLineItems" xlink:label="sgly_ScheduleOfIncomeTaxExpensesLineItems_1424" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract" xlink:label="us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract_1425" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_1426" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1421_default" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgly_ScheduleOfIncomeTaxExpensesLineItems_1424" xlink:to="sgly_ScheduleOfIncomeTaxExpensesTable_1419" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgly_ScheduleOfIncomeTaxExpensesTable_1419" xlink:to="srt_StatementGeographicalAxis_1420" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_1420" xlink:to="srt_SegmentGeographicalDomain_1421" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1421" xlink:to="country_US_1422" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1421" xlink:to="country_CN_1423" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgly_ScheduleOfIncomeTaxExpensesLineItems_1424" xlink:to="us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract_1425" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract_1425" xlink:to="us-gaap_IncomeTaxExpenseBenefit_1426" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_1420" xlink:to="srt_SegmentGeographicalDomain_1421_default" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://singularityfuturetechnologyltd.com/20260630/role/IncomeTaxesScheduleofDeferredTaxAssetsDetails" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts_1435" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_1436" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="us-gaap_DeferredTaxAssetsGross_1437" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_1438" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_1439" />
    <link:loc xlink:type="locator" xlink:href="sgly-20260630.xsd#sgly_ScheduleOfDeferredTaxAssetsAbstract" xlink:label="sgly_ScheduleOfDeferredTaxAssetsAbstract_1428" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTable_1429" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_1430" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1431" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US" xlink:label="country_US_1432" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CN" xlink:label="country_CN_1433" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_1431_default" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts_1435" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_1436" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_DeferredTaxAssetsGross_1437" />
    <link:definitionArc xlink:type="arc" order="13.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_1438" />
    <link:definitionArc xlink:type="arc" order="14.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_DeferredTaxAssetsLiabilitiesNet_1439" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="true" use="optional" xbrldt:contextElement="segment" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_1434" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTable_1429" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationTable_1429" xlink:to="srt_StatementGeographicalAxis_1430" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis_1430" xlink:to="srt_SegmentGeographicalDomain_1431" />
    <link:definitionArc xlink:type="arc" order="11.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1431" xlink:to="country_US_1432" />
    <link:definitionArc xlink:type="arc" order="12.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain_1431" xlink:to="country_CN_1433" />
    <link:definitionArc xlink:type="arc" order="10.00000" priority="1" xbrldt:closed="false" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis_1430" xlink:to="srt_SegmentGeographicalDomain_1431_default" />
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-roles-2026.xsd#eedm1" xlink:type="simple" />
  <link:definitionLink xlink:role="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="extended" xlink:title="definitionLink">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration" xlink:label="us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ChiefExecutiveOfficerMember" xlink:label="srt_ChiefExecutiveOfficerMember" />
    <link:definitionArc xlink:type="arc" order="0" priority="1" xbrldt:closed="true" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration" />
    <link:definitionArc xlink:type="arc" order="1" priority="1" xbrldt:closed="true" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="srt_ChiefExecutiveOfficerMember" />
  </link:definitionLink>
</link:linkbase>
