Ketch n.  Naut.
  1. An almost obsolete form of sailing vessel, with a mainmast and a mizzenmast, -- usually from one hundred to two hundred and fifty tons burden.
  Bomb ketch. See under Bomb.
  Bomb n.
  1. A great noise; a hollow sound. [Obs.]
     A pillar of iron . . . which if you had struck, would make . . . a great bomb in the chamber beneath.   --Bacon.
  2. Mil. A shell; esp. a spherical shell, like those fired from mortars. See Shell.
  3. A bomb ketch.
  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.”