The Collaborative International Dictionary of English v.0.48:

Listen \Lis"ten\ (l[i^]s"'n), v. i. [imp. & p. p. Listened
   (l[i^]s"'nd); p. pr. & vb. n. Listening.] [OE. listnen,
   listen, lustnen, lusten, AS. hlystan; akin to hlyst hearing,
   OS. hlust, Icel. hlusta to listen, hlust ear, AS. hlosnian to
   wait in suspense, OHG. hlos[=e]n to listen, Gr. kly`ein, and
   E. loud. [root]41. See Loud, and cf. List to listen.]
   1. To give close attention with the purpose of hearing; to
      give ear; to hearken; to attend.
      [1913 Webster]

            When we have occasion to listen, and give a more
            particular attention to some sound, the tympanum is
            drawn to a more than ordinary tension. --Holder.
      [1913 Webster]

   2. To give heed; to yield to advice; to follow admonition; to
      obey.
      [1913 Webster]

            Listen to me, and by me be ruled.     --Tennyson.
      [1913 Webster]

   To listen after, to take an interest in. [Obs.]
      [1913 Webster]

            Soldiers note forts, armories, and magazines;
            scholars listen after libraries, disputations, and
            professors.                           --Fuller.

   Syn: To attend; hearken. See Attend.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

listening \listening\ n.
   the act of hearing attentively.

   Syn: hearing.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

listening
    n 1: the act of hearing attentively; "you can learn a lot by
         just listening"; "they make good music--you should give
         them a hearing" [syn: listening, hearing]