Vault n.
 1. Arch. An arched structure of masonry, forming a ceiling or canopy.
    The long-drawn aisle and fretted vault.   --Gray.
 2. An arched apartment; especially, a subterranean room, used for storing articles, for a prison, for interment, or the like; a cell; a cellar. “Charnel vaults.”
    The silent vaults of death.   --Sandys.
    To banish rats that haunt our vault.   --Swift.
 3. The canopy of heaven; the sky.
    That heaven's vault should crack.   --Shak.
 4.  A leap or bound. Specifically: -- (a) Man. The bound or leap of a horse; a curvet. (b) A leap by aid of the hands, or of a pole, springboard, or the like.
 Note: ☞ The l in this word was formerly often suppressed in pronunciation.
 Barrel vault, Cradle vault, Cylindrical vault, or Wagon vault Arch., a kind of vault having two parallel abutments, and the same section or profile at all points.  It may be rampant, as over a staircase (see Rampant vault, under Rampant), or curved in plan, as around the apse of a church.
 Coved vault. Arch. See under 1st Cove, v. t.
 Groined vault Arch., a vault having groins, that is, one in which different cylindrical surfaces intersect one another, as distinguished from a barrel, or wagon, vault.
 Rampant vault. Arch. See under Rampant.
 Ribbed vault Arch., a vault differing from others in having solid ribs which bear the weight of the vaulted surface. True Gothic vaults are of this character.
 Vault light, a partly glazed plate inserted in a pavement or ceiling to admit light to a vault below.


 groined vault
      n : two barrel vaults intersecting at right angles