The Collaborative International Dictionary of English v.0.48:

Compartment \Com*part"ment\, n. [F. compartiment, OF. compartir
   to divide. See Compart.]
   1. One of the parts into which an inclosed portion of space
      is divided, as by partitions, or lines; as, the
      compartments of a cabinet, a house, or a garden.
      [1913 Webster]

            In the midst was placed a large compartment composed
            of grotesque work.                    --Carew.
      [1913 Webster]

   2. (Shipbuilding) One of the sections into which the hold of
      a ship is divided by water-tight bulkheads.
      [1913 Webster] compartmental

WordNet (r) 3.0 (2006):

compartment
    n 1: a space into which an area is subdivided
    2: a partitioned section, chamber, or separate room within a
       larger enclosed area

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "compartment":
   alcove, bay, below, between-decks, boiler room, booth, box, brig,
   bunker, cabin, caboose, camboose, cavity, cell, cellule, chamber,
   chart room, conning tower, crib, crypt, cubicle, division,
   enclosed space, engine room, forecastle, forepeak, galley, head,
   hold, hole, hollow, lazaret, locker, manger, niche, part,
   partition, pew, pilothouse, quarters, radio room, roundhouse,
   sail loft, section, sick bay, slot, space, stall, stateroom,
   stokehold, topside, vault, wardroom