The Collaborative International Dictionary of English v.0.48:

Gunroom \Gun"room`\ (g[u^]n"r[=oo]m`), n. (Naut.)
   An apartment on the after end of the lower gun deck of a ship
   of war, usually occupied as a messroom by the commissioned
   officers, except the captain; -- called wardroom in the
   United States navy.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wardroom \Ward"room`\, n.
   1. (Naut.) A room occupied as a messroom by the commissioned
      officers of a war vessel. See Gunroom. --Totten.
      [1913 Webster]

   2. A room used by the citizens of a city ward, for meetings,
      political caucuses, elections, etc. [U. S.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

wardroom
    n 1: military quarters for dining and recreation for officers of
         a warship (except the captain)