The Collaborative International Dictionary of English v.0.48:

MASH \MASH\, MASH \M*A*S*H\, n. (Mil.)
   An abbreviation for Mobile Army Surgical Hospital,
   consisting of the equipment and personnel required to perform
   emergency operations on injured soldiers, located in tents
   near the front lines of combat; as, he worked in the 25th
   MASH.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Mash \Mash\, n.
   A mesh. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mash \Mash\, n. [Akin to G. meisch, maisch, meische, maische,
   mash, wash, and prob. to AS. miscian to mix. See Mix.]
   [1913 Webster]
   1. A mass of mixed ingredients reduced to a soft pulpy state
      by beating or pressure; a mass of anything in a soft pulpy
      state. Specifically (Brewing), ground or bruised malt, or
      meal of rye, wheat, corn, or other grain (or a mixture of
      malt and meal) steeped and stirred in hot water for making
      the wort.
      [1913 Webster]

   2. A mixture of meal or bran and water fed to animals.
      [1913 Webster]

   3. A mess; trouble. [Obs.] --Beau. & Fl.
      [1913 Webster]

   Mash tun, a large tub used in making mash and wort.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mash \Mash\, v. t. [imp. & p. p. Mashed; p. pr. & vb. n.
   Mashing.] [Akin to G. meischen, maischen, to mash, mix, and
   prob. to mischen, E. mix. See 2d Mash.]
   To convert into a mash; to reduce to a soft pulpy state by
   beating or pressure; to bruise; to crush; as, to mash apples
   in a mill, or potatoes with a pestle. Specifically (Brewing),
   to convert, as malt, or malt and meal, into the mash which
   makes wort.
   [1913 Webster]

   Mashing tub, a tub for making the mash in breweries and
      distilleries; -- called also mash tun, and mash vat.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mash
    n 1: a mixture of mashed malt grains and hot water; used in
         brewing
    2: mixture of ground animal feeds
    v 1: to compress with violence, out of natural shape or
         condition; "crush an aluminum can"; "squeeze a lemon" [syn:
         squash, crush, squelch, mash, squeeze]
    2: talk or behave amorously, without serious intentions; "The
       guys always try to chat up the new secretaries"; "My husband
       never flirts with other women" [syn: chat up, flirt,
       dally, butterfly, coquet, coquette, romance,
       philander, mash]
    3: reduce to small pieces or particles by pounding or abrading;
       "grind the spices in a mortar"; "mash the garlic" [syn:
       grind, mash, crunch, bray, comminute]