The Collaborative International Dictionary of English v.0.48:

Bulkhead \Bulk"head`\, n. [See Bulk part of a building.]
   1. (Naut.) A partition in a vessel, to separate apartments on
      the same deck.
      [1913 Webster]

   2. A structure of wood or stone, to resist the pressure of
      earth or water; a partition wall or structure, as in a
      mine; the limiting wall along a water front.
      [1913 Webster]

   Bulked line, a line beyond which a wharf must not project;
      -- usually, the harbor line.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bulkhead
    n 1: a partition that divides a ship or plane into compartments

Moby Thesaurus II by Grady Ward, 1.0:

136 Moby Thesaurus words for "bulkhead":
   French door, anchorage, anchorage ground, arch dam, archway,
   back door, backstop, bamboo curtain, bank, bar, barrage, barrier,
   barway, basin, bear-trap dam, beaver dam, berth, boom, brattice,
   breakwater, breastwork, brick wall, buffer, buffer state, bulwark,
   bumper, carriage entrance, cellar door, cellarway, cloison,
   cofferdam, collision mat, cushion, dam, defense, diaphragm, dike,
   dissepiment, ditch, dividing line, dividing wall, division, dock,
   dockage, dockyard, door, doorjamb, doorpost, doorway, dry dock,
   earthwork, embankment, fence, fender, front door, gate, gatepost,
   gateway, gravity dam, groin, harbor, harborage, hatch, hatchway,
   haven, hydraulic-fill dam, interseptum, iron curtain, jam, jetty,
   jutty, landing, landing place, landing stage, leaping weir, levee,
   lintel, logjam, marina, mat, midriff, midsection, milldam, moat,
   mole, moorings, mound, pad, panel, parapet, paries, partition,
   party wall, pier, porch, port, portal, portcullis, porte cochere,
   postern, property line, propylaeum, protected anchorage, pylon,
   quay, rampart, road, roadblock, roads, roadstead, rock-fill dam,
   scuttle, seaport, seawall, separation, septulum, septum, shipyard,
   shock pad, shutter dam, side door, slip, stile, stone wall,
   storm door, threshold, tollgate, trap, trap door, turnpike,
   turnstile, wall, weir, wharf, wicket dam, work