The Collaborative International Dictionary of English v.0.48:

Mortar \Mor"tar\, v. t.
   To plaster or make fast with mortar.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mortar \Mor"tar\, n. [F. mortier. See Mortar a vessel.]
   A chamber lamp or light. [Obs.] --Chaucer.
   [1913 Webster] mortarboard

The Collaborative International Dictionary of English v.0.48:

Mortar \Mor"tar\, n. [OE. morter, AS. mort[=e]re, L. mortarium:
   cf. F. mortier mortar. Cf. sense 2 (below), also 2d Mortar,
   Martel, Morter.]
   1. A strong vessel, commonly in form of an inverted bell, in
      which substances are pounded or rubbed with a pestle.
      [1913 Webster]

   2. [F. mortier, fr. L. mortarium mortar (for trituarating).]
      (Mil.) A short piece of ordnance, used for throwing bombs,
      carcasses, shells, etc., at high angles of elevation, as
      45[deg], and even higher; -- so named from its resemblance
      in shape to the utensil above described.
      [1913 Webster]

   Mortar bed (Mil.), a framework of wood and iron, suitably
      hollowed out to receive the breech and trunnions of a
      mortar.

   Mortar boat or Mortar vessel (Naut.), a boat strongly
      built and adapted to carrying a mortar or mortars for
      bombarding; a bomb ketch.

   Mortar piece, a mortar. [Obs.] --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mortar \Mor"tar\, n. [OE. mortier, F. mortier, L. mortarium
   mortar, a large basin or trough in which mortar is made, a
   mortar (in sense 1, above). See 1st Mortar.] (Arch.)
   A building material made by mixing lime, cement, or plaster
   of Paris, with sand, water, and sometimes other materials; --
   used in masonry for joining stones, bricks, etc., also for
   plastering, and in other ways.
   [1913 Webster]

   Mortar bed, a shallow box or receptacle in which mortar is
      mixed.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mortar
    n 1: a muzzle-loading high-angle gun with a short barrel that
         fires shells at high elevations for a short range [syn:
         mortar, howitzer, trench mortar]
    2: used as a bond in masonry or for covering a wall
    3: a bowl-shaped vessel in which substances can be ground and
       mixed with a pestle
    v 1: plaster with mortar; "mortar the wall"

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "mortar":
   adobe, aim at, alembic, anvil, ashlar, barrage, blast, blitz,
   bombard, brick, bricks and mortar, caldron, cannon, cannonade,
   cement, clinker, commence firing, concrete, covering materials,
   crucible, enfilade, engine, ferroconcrete, fire a volley, fire at,
   fire upon, firebrick, flag, flagstone, flooring, fusillade, grout,
   lath and plaster, lathe, machine, masonry, mastic, melting pot,
   motor, open fire, open up on, parget, pavement, paving,
   paving material, pepper, plaster, plasters, pop at,
   prestressed concrete, rake, retort, roofage, roofing, roughcast,
   shell, shoot, shoot at, siding, snipe, snipe at, stone, strafe,
   stucco, take aim at, test tube, tile, tiling, torpedo, transducer,
   transformer, walling, zero in on



Easton's 1897 Bible Dictionary:

Mortar
   (Heb. homer), cement of lime and sand (Gen. 11:3; Ex. 1:14);
   also potter's clay (Isa. 41:25; Nah. 3:14). Also Heb. 'aphar,
   usually rendered "dust," clay or mud used for cement in building
   (Lev. 14:42, 45).

     Mortar for pulverizing (Prov. 27:22) grain or other substances
   by means of a pestle instead of a mill. Mortars were used in the
   wilderness for pounding the manna (Num. 11:8). It is commonly
   used in Palestine at the present day to pound wheat, from which
   the Arabs make a favourite dish called kibby.