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.
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            Is the soul affiliated to God, or is it estranged
            and in rebellion?                     --I. Taylor.
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   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.
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   3. To connect in the way of descent; to trace origin to.
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            How do these facts tend to affiliate the faculty of
            hearing upon the aboriginal vegetative processes?
                                                  --H. Spencer.
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   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.
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   Affiliated societies, societies connected with a central
      society, or with each other.
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