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.
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            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.
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   2. To give heed; to yield to advice; to follow admonition; to
      obey.
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            Listen to me, and by me be ruled.     --Tennyson.
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   To listen after, to take an interest in. [Obs.]
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            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:

Listen \Lis"ten\, v. t.
   To attend to. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

listen
    v 1: hear with intention; "Listen to the sound of this cello"
    2: listen and pay attention; "Listen to your father"; "We must
       hear the expert before we make a decision" [syn: listen,
       hear, take heed]
    3: pay close attention to; give heed to; "Heed the advice of the
       old men" [syn: heed, mind, listen]