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.
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   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.
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   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.
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The Collaborative International Dictionary of English v.0.48:

Bomb \Bomb\, n. [F. bombe bombshell, fr. L. bombus a humming or
   buzzing noise, Gr. ?.]
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   1. A great noise; a hollow sound. [Obs.]
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            A pillar of iron . . . which if you had struck,
            would make . . . a great bomb in the chamber
            beneath.                              --Bacon.
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   2. (Mil.) A shell; esp. a spherical shell, like those fired
      from mortars. See Shell.
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   3. A bomb ketch.
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   Bomb chest (Mil.), a chest filled with bombs, or only with
      gunpowder, placed under ground, to cause destruction by
      its explosion.

   Bomb ketch, Bomb vessel (Naut.), a small ketch or vessel,
      very strongly built, on which mortars are mounted to be
      used in naval bombardments; -- called also mortar
      vessel.

   Bomb lance, a lance or harpoon with an explosive head, used
      in whale fishing.

   Volcanic bomb, a mass of lava of a spherical or pear shape.
      "I noticed volcanic bombs." --Darwin.
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