Source : Webster's Revised Unabridged Dictionary (1913)

Terminal \Ter"mi*nal\ (-nal), a. [L. terminals: cf. F. terminal.
   See {Term}, n.]
   1. Of or pertaining to the end or extremity; forming the
      extremity; as, a terminal edge.

   2. (Bot.) Growing at the end of a branch or stem;
      terminating; as, a terminal bud, flower, or spike.

   {Terminal moraine}. See the Note under {Moraine}.

   {Terminal statue}. See {Terminus}, n., 2 and 3.

   {Terminal velocity}.
      (a) The velocity acquired at the end of a body's motion.
      (b) The limit toward which the velocity of a body
          approaches, as of a body falling through the air.

Source : WordNet®

terminal velocity
     n : the constant maximum velocity reached by a body falling
         through the atmosphere under the attraction of gravity