NOUN (4)

1. a vertical spar for supporting sails;

2. nuts of forest trees (as beechnuts and acorns) accumulated on the ground;

3. nuts of forest trees used as feed for swine;

4. any sturdy upright pole;

The Collaborative International Dictionary of English v.0.48:

Mast \Mast\ (m[.a]st), n. [AS. maest, fem.; akin to G. mast, and
   E. meat. See Meat.]
   The fruit of the oak and beech, or other forest trees; nuts;
   acorns.
   [1913 Webster]

         Oak mast, and beech, . . . they eat.     --Chapman.
   [1913 Webster]

         Swine under an oak filling themselves with the mast.
                                                  --South.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mast \Mast\, v. t. [imp. & p. p. Masted; p. pr. & vb. n.
   Masting.]
   To furnish with a mast or masts; to put the masts of in
   position; as, to mast a ship.
   [1913 Webster] Mastaba

The Collaborative International Dictionary of English v.0.48:

Mast \Mast\, n. [AS. maest, masc.; akin to D., G., Dan., & Sw.
   mast, Icel. mastr, and perh. to L. malus.]
   [1913 Webster]
   1. (Naut.) A pole, or long, strong, round piece of timber, or
      spar, set upright in a boat or vessel, to sustain the
      sails, yards, rigging, etc. A mast may also consist of
      several pieces of timber united by iron bands, or of a
      hollow pillar of iron or steel.
      [1913 Webster]

            The tallest pine
            Hewn on Norwegian hills, to be the mast
            Of some great ammiral.                --Milton.
      [1913 Webster]

   Note: The most common general names of masts are foremast,
         mainmast, and mizzenmast, each of which may be made
         of separate spars.
         [1913 Webster]

   2. (Mach.) The vertical post of a derrick or crane.
      [1913 Webster]

   3. (Aeronautics) A spar or strut to which tie wires or guys
      are attached for stiffening purposes.
      [Webster 1913 Suppl.]

   Afore the mast, Before the mast. See under Afore, and
      Before.

   Mast coat. See under Coat.

   Mast hoop, one of a number of hoops attached to the fore
      edge of a boom sail, which slip on the mast as the sail is
      raised or lowered; also, one of the iron hoops used in
      making a made mast. See Made.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mast
    n 1: a vertical spar for supporting sails
    2: nuts of forest trees (as beechnuts and acorns) accumulated on
       the ground
    3: nuts of forest trees used as feed for swine
    4: any sturdy upright pole

Moby Thesaurus II by Grady Ward, 1.0:

144 Moby Thesaurus words for "mast":
   advocate, alpenstock, antenna tower, arm, athletic supporter, back,
   backbone, backing, bandeau, barbican, bare pole, bearer, belfry,
   bell tower, boom, bowsprit, bra, brace, bracer, bracket, brassiere,
   bumpkin, buttress, campanile, cane, carrier, cervix, club,
   colossus, column, corset, crook, crossjack yard, crosstree, crutch,
   cupola, derrick, dolphin striker, dome, fire tower,
   flying jib boom, fore jack, fore-skysail mast, fore-skysail yard,
   fore-topgallant mast, fore-topgallant yard, fore-topmast, foremast,
   foreroyal mast, foreroyal yard, foreyard, foundation garment,
   fulcrum, gaff, girdle, gooseneck, guy, guywire, jack, jib boom,
   jock, jockstrap, king post, lantern, lazy jack, lighthouse,
   lower boom, main-royal mast, main-royal yard, main-skysail mast,
   main-topgallant mast, mainmast, mainstay, maintainer, martello,
   martello tower, masthead, minaret, mizzen, mizzen-royal mast,
   mizzenmast, monument, neck, obelisk, observation tower, pagoda,
   pilaster, pillar, pinnacle, pole, prop, pylon, pyramid, reinforce,
   reinforcement, reinforcer, rest, resting place, rigging, shaft,
   shoulder, shroud, skysail yard, skyscraper, spanker boom,
   spanker gaff, spar, spars, spine, spire, spreader, sprit, staff,
   standing rigging, standpipe, stave, stay, steeple, stick,
   stiffener, strengthener, stupa, support, supporter, sustainer,
   tack bumpkin, television mast, timber, tope, topgallant mast,
   topgallant yard, topmast, tour, tower, tree, turret, upholder,
   walking stick, water tower, whisker boom, whisker pole,
   windmill tower, yard, yardarm