Source : Webster's Revised Unabridged Dictionary (1913)

Prisoner \Pris"on*er\, n. [F. prisonnier.]
   1. One who is confined in a prison. --Piers Plowman.

   2. A person under arrest, or in custody, whether in prison or
      not; a person held in involuntary restraint; a captive;
      as, a prisoner at the bar of a court. --Bouvier.

            Prisoner of Hope thou art, -- look up and sing.
                                                  --Keble.

   {Prisoner's base}. See {Base}, n., 24.

Source : WordNet®

prisoner
     n : a person who is confined; especially a prisoner of war [syn:
          {captive}]