The Collaborative International Dictionary of English v.0.48:

Join \Join\ (join), v. t. [imp. & p. p. Joined (joind); p. pr.
   & vb. n. Joining.] [OE. joinen, joignen, F. joindre, fr. L.
   jungere to yoke, bind together, join; akin to jugum yoke. See
   Yoke, and cf. Conjugal, Junction, Junta.]
   [1913 Webster]
   1. To bring together, literally or figuratively; to place in
      contact; to connect; to couple; to unite; to combine; to
      associate; to add; to append.
      [1913 Webster]

            Woe unto them that join house to house. --Is. v. 8.
      [1913 Webster]

            Held up his left hand, which did flame and burn
            Like twenty torches joined.           --Shak.
      [1913 Webster]

            Thy tuneful voice with numbers join.  --Dryden.
      [1913 Webster]

   2. To associate one's self to; to be or become connected
      with; to league one's self with; to unite with; as, to
      join a party; to join the church.
      [1913 Webster]

            We jointly now to join no other head. --Dryden.
      [1913 Webster]

   3. To unite in marriage.
      [1913 Webster]

            He that joineth his virgin in matrimony. --Wyclif.
      [1913 Webster]

            What, therefore, God hath joined together, let not
            man put asunder.                      --Matt. xix.
                                                  6.
      [1913 Webster]

   4. To enjoin upon; to command. [Obs. & R.]
      [1913 Webster]

            They join them penance, as they call it. --Tyndale.
      [1913 Webster]

   5. To accept, or engage in, as a contest; as, to join
      encounter, battle, issue. --Milton.
      [1913 Webster]

   6. To meet with and accompany; as, we joined them at the
      restaurant.
      [PJC]

   7. To combine with (another person) in performing some
      activity; as, join me in welcoming our new president.
      [PJC]

   To join battle, To join issue. See under Battle,
      Issue.

   Syn: To add; annex; unite; connect; combine; consociate;
        couple; link; append. See Add.
        [1913 Webster]

WordNet (r) 3.0 (2006):

joining
    n 1: the act of bringing two things into contact (especially for
         communication); "the joining of hands around the table";
         "there was a connection via the internet" [syn: joining,
         connection, connexion]

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "joining":
   accession, addition, adjunct, adjunction, affixation,
   agglutination, ankle, annexation, articulation, attachment,
   augmentation, binding, boundary, butt, cervix, clinch, closure,
   collision course, combinative, communicating, confrontation,
   conjunctive, connecting, connecting link, connecting rod,
   connection, connectional, connective, copulative, coupling,
   dovetail, elbow, embrace, encounter, gliding joint, hinge,
   hinged joint, hip, increase, intercommunicating, interface, join,
   joint, junction, juncture, juxtaposition, knee, knuckle, link,
   linking, meeting, miter, mortise, narrow squeak, near thing,
   near-miss, neck, pivot, pivot joint, prefixation, rabbet,
   reinforcement, rencontre, scarf, seam, shoulder, stitch,
   suffixation, superaddition, superfetation, superjunction,
   superposition, supplementation, suture, symphysis, tie rod, toggle,
   toggle joint, union, uniting, weld, wrist