The Collaborative International Dictionary of English v.0.48:

Sitting \Sit"ting\, n.
   1. The state or act of one who sits; the posture of one who
      occupies a seat.
      [1913 Webster]

   2. A seat, or the space occupied by or allotted for a person,
      in a church, theater, etc.; as, the hall has 800 sittings.
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   3. The act or time of sitting, as to a portrait painter,
      photographer, etc.
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   4. The actual presence or meeting of any body of men in their
      seats, clothed with authority to transact business; a
      session; as, a sitting of the judges of the King's Bench,
      or of a commission.
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            The sitting closed in great agitation. --Macaulay.
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   5. The time during which one sits while doing something, as
      reading a book, playing a game, etc.
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            For the understanding of any one of St. Paul's
            Epistles I read it all through at one sitting.
                                                  --Locke.
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   6. A brooding over eggs for hatching, as by fowls.
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            The male bird . . . amuses her [the female] with his
            songs during the whole time of her sitting.
                                                  --Addison.
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   Sitting room, an apartment where the members of a family
      usually sit, as distinguished from a drawing-room, parlor,
      chamber, or kitchen.
      [1913 Webster] Situate

WordNet (r) 3.0 (2006):

sitting 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]