The Collaborative International Dictionary of English v.0.48:

living room \liv"ing room`\
   A room in a house used by all or most of the family, where
   the family entertain guests or relax together for leisure
   activities. It usually contains at least one couch, and does
   not contain a dining table.
   [PJC]

WordNet (r) 3.0 (2006):

living room
    n 1: a room in a private house or establishment where people can
         sit and talk and relax [syn: living room, living-room,
         sitting room, front room, parlor, parlour]