What is "mortar bed"

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.

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.

   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.

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.

Mortar bed, a shallow box or receptacle in which mortar is mixed.