The Collaborative International Dictionary of English v.0.48:

Affiliate \Af*fil"i*ate\, v. t. [imp. & p. p. Affiliated; p.
   pr. & vb. n. Affiliating.] [LL. adfiliare, affiliare, to
   adopt as son; ad + filius son: cf. F. affilier.]
   1. To adopt; to receive into a family as a son; hence, to
      bring or receive into close connection; to ally.
      [1913 Webster]

            Is the soul affiliated to God, or is it estranged
            and in rebellion?                     --I. Taylor.
      [1913 Webster]

   2. To fix the paternity of; -- said of an illegitimate child;
      as, to affiliate the child to (or on or upon) one man
      rather than another.
      [1913 Webster]

   3. To connect in the way of descent; to trace origin to.
      [1913 Webster]

            How do these facts tend to affiliate the faculty of
            hearing upon the aboriginal vegetative processes?
                                                  --H. Spencer.
      [1913 Webster]

   4. To attach (to) or unite (with); to receive into a society
      as a member, and initiate into its mysteries, plans, etc.;
      -- followed by to or with.
      [1913 Webster]

   Affiliated societies, societies connected with a central
      society, or with each other.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

affiliated \affiliated\ adj.
   1. 1 being joined in close association affiliated clubs

   Syn: attached, connected
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

affiliated
    adj 1: being joined in close association; "affiliated clubs";
           "all art schools whether independent or attached to
           universities" [syn: affiliated, attached,
           connected]

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "affiliated":
   affiliate, agnate, akin, allied, associate, associated, attached,
   avuncular, bound, bracketed, cabalistic, closely related, cognate,
   collateral, combined, confederate, confederated, congeneric,
   conjugate, connate, connatural, connected, consanguine,
   consanguinean, consanguineous, conspiratorial, corporate,
   correlated, coupled, distantly related, enate, enleagued, federate,
   federated, foster, german, germane, implicated, in cahoots,
   in league, in partnership, in with, incident, interlinked,
   interlocked, interrelated, involved, joined, kindred, knotted,
   leagued, linked, married, matrilateral, matrilineal, matroclinous,
   novercal, of that ilk, of that kind, of the blood, paired,
   parallel, partners with, patrilateral, patrilineal, patroclinous,
   related, sib, sibling, spliced, teamed, tied, twinned, united,
   uterine, wed, wedded, yoked