The Collaborative International Dictionary of English v.0.48:

Parlor \Par"lor\, n. [OE. parlour, parlur, F. parloir, LL.
   parlatorium. See Parley.] [Written also parlour.]
   1. A room for business or social conversation, for the
      reception of guests, etc. Specifically:
      (a) The apartment in a monastery or nunnery where the
          inmates are permitted to meet and converse with each
          other, or with visitors and friends from without.
          --Piers Plowman.
      (b) In large private houses, a sitting room for the family
          and for familiar guests, -- a room for less formal
          uses than the drawing-room. Esp., in modern times, the
          dining room of a house having few apartments, as a
          London house, where the dining parlor is usually on
          the ground floor.
      (c) Commonly, in the United States, a drawing-room, or the
          room where visitors are received and entertained; a
          room in a private house where people can sit and talk
          and relax, not usually the same as the dining room.
          [1913 Webster +PJC]

   Note: "In England people who have a drawing-room no longer
         call it a parlor, as they called it of old and till
         recently." --Fitzed. Hall.
         [1913 Webster]

   2. A room in an inn or club where visitors can be received.
      [WordNet 1.5]

   Parlor car. See Palace car, under Car.
      [1913 Webster]

WordNet (r) 3.0 (2006):

parlor
    n 1: reception room in an inn or club where visitors can be
         received [syn: parlor, parlour]
    2: 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]