The Collaborative International Dictionary of English v.0.48:

Related \Re*lat"ed\ (-l?t"?d), p. p. & a.
   1. Allied by kindred; connected by blood or alliance,
      particularly by consanguinity; as, persons related in the
      first or second degree.
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   2. Standing in relation or connection; as, the electric and
      magnetic forcec are closely related.
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   3. Narrated; told.
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   4. (Mus.) Same as Relative, 4.
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The Collaborative International Dictionary of English v.0.48:

Relate \Re*late"\ (r?-l?t"), v. t. [imp. & p. p. Related; p.
   pr. & vb. n. Relating.] [F. relater to recount, LL.
   relatare, fr. L. relatus, used as p. p. of referre. See
   Elate, and cf. Refer.]
   1. To bring back; to restore. [Obs.]
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            Abate your zealous haste, till morrow next again
            Both light of heaven and strength of men relate.
                                                  --Spenser.
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   2. To refer; to ascribe, as to a source. [Obs. or R.]
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   3. To recount; to narrate; to tell over.
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            This heavy act with heavy heart relate. --Shak.
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   4. To ally by connection or kindred.
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   To relate one's self, to vent thoughts in words. [R.]
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   Syn: To tell; recite; narrate; recount; rehearse; report;
        detail; describe.
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WordNet (r) 3.0 (2006):

related
    adj 1: being connected either logically or causally or by shared
           characteristics ; "painting and the related arts";
           "school-related activities"; "related to micelle
           formation is the...ability of detergent actives to
           congregate at oil-water interfaces" [syn: related,
           related to] [ant: unrelated]
    2: connected by kinship, common origin, or marriage [ant:
       unrelated]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "related":
   affiliate, affiliated, affinal, agnate, akin, allied, associate,
   associated, avuncular, bound, bracketed, closely related, cognate,
   collateral, common, congeneric, congenerous, conjugate, connate,
   connatural, connected, consanguine, consanguinean, consanguineous,
   coordinated, correlated, coupled, distantly related, enate, foster,
   genetically related, german, germane, implicated, interconnected,
   interdependent, interlinked, interlocked, interrelated, involved,
   joined, joint, kin, kindred, knotted, linked, matrilateral,
   matrilineal, matroclinous, mutual, novercal, of common source,
   of that ilk, of that kind, of the blood, parallel, patrilateral,
   patrilineal, patroclinous, reciprocal, related by blood, sib,
   sibling, spliced, tied, tied up, twinned, uterine, wed, wedded,
   yoked