Source : Webster's Revised Unabridged Dictionary (1913)

Rejoin \Re*join"\ (r?-join"), v. t. [imp. & p. p. {Rejoined}
   (-joind"); p. pr. & vb. n. {Rejoining}.] [F. rejoindre; pref.
   re- re- + joindre to join. See {Join}, and cf. {Rejoinder}.]
   1. To join again; to unite after separation.

   2. To come, or go, again into the presence of; to join the
      company of again.

            Meet and rejoin me, in the pensive grot. --Pope.

   3. To state in reply; -- followed by an object clause.

Rejoin \Re*join"\, v. i.
   1. To answer to a reply.

   2. (Law) To answer, as the defendant to the plaintiff's
      replication.

Source : WordNet®

rejoin
     v 1: join again
     2: answer back [syn: {retort}, {come back}, {repay}, {return},
        {riposte}]