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