Source : Webster's Revised Unabridged Dictionary (1913)

Concurrent \Con*cur"rent\, n.
   1. One who, or that which, concurs; a joint or contributory
      cause.

            To all affairs of importance there are three
            necessary concurrents . . . time, industry, and
            faculties.                            --Dr. H. More.

   2. One pursuing the same course, or seeking the same objects;
      hence, a rival; an opponent.

            Menander . . . had no concurrent in his time that
            came near unto him.                   --Holland.

   3. (Chron.) One of the supernumerary days of the year over
      fifty-two complete weeks; -- so called because they concur
      with the solar cycle, the course of which they follow.

Concurrent \Con*cur"rent\, a. [F. concurrent, L. concurrens, p.
   pr. of concurrere.]
   1. Acting in conjunction; agreeing in the same act or
      opinion; contributing to the same event or effect;
      co["o]perating.

            I join with these laws the personal presence of the
            kings' son, as a concurrent cause of this
            reformation.                          --Sir J.
                                                  Davies.

            The concurrent testimony of antiquity. --Bp.
                                                  Warburton.

   2. Conjoined; associate; concomitant; existing or happening
      at the same time.

            There is no difference the concurrent echo and the
            iterant but the quickness or slowness of the return.
                                                  --Bacon.

            Changes . . . concurrent with the visual changes in
            the eye.                              --Tyndall.

   3. Joint and equal in authority; taking cognizance of similar
      questions; operating on the same objects; as, the
      concurrent jurisdiction of courts.

   4. (Geom.) Meeting in one point.

   Syn: Meeting; uniting; accompanying; conjoined; associated;
        coincident; united.

Source : WordNet®

concurrent
     adj : occurring or operating at the same time; "a series of
           coincident events" [syn: {coincident}, {coincidental},
           {coinciding}, {cooccurring}, {simultaneous}]