[1] : The Collaborative International Dictionary of English v.0.48

vault \vault\ vaddlt; see note, below, n. oe. voute, of.
   voute, volte, f. vo^ute, ll. volta, for voluta, volutio,
   fr. l. volvere, volutum, to roll, to turn about. see
   voluble, and cf. vault a leap, volt a turn, volute.
   1913 webster
   1. arch. an arched structure of masonry, forming a ceiling
      or canopy.
      1913 webster

            the long-drawn aisle and fretted vault. --gray.
      1913 webster

   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." --milton.
      1913 webster

            the silent vaults of death.           --sandys.
      1913 webster

            to banish rats that haunt our vault.  --swift.
      1913 webster

   3. the canopy of heaven; the sky.
      1913 webster

            that heaven's vault should crack.     --shak.
      1913 webster

   4. f. volte, it. volta, originally, a turn, and the same
      word as volta an arch. see the etymology above. 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.
          1913 webster

   note: the l in this word was formerly often suppressed in
         pronunciation.
         1913 webster

   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.
      1913 webster
see also:
voluble vault volt volute barrel vault cradle vault 
cylindrical vault wagon vault rampant vault rampant coved vault 
cove groined vault rampant vault ribbed vault vault light 

[2] : The Collaborative International Dictionary of English v.0.48

barrel \bar"rel\ ba^r"re^l, n.oe. barel, f. baril, prob.
   fr. barre bar. cf. barricade.
   1. a round vessel or cask, of greater length than breadth,
      and bulging in the middle, made of staves bound with
      hoops, and having flat ends or heads; as, a cracker
      barrel. sometimes applied to a similar cylindrical
      container made of metal, usually called a drum.
      1913 webster +pjc

   2. the quantity which constitutes a full barrel. this varies
      for different articles and also in different places for
      the same article, being regulated by custom or by law. a
      barrel of wine is 311/2 gallons; a barrel of flour is 196
      pounds.
      1913 webster

   3. a solid drum, or a hollow cylinder or case; as, the barrel
      of a windlass; the barrel of a watch, within which the
      spring is coiled.
      1913 webster

   4. a metallic tube, as of a gun, from which a projectile is
      discharged. --knight.
      1913 webster

   5. a jar. obs. --1 kings xvii. 12.
      1913 webster

   6. zool. the hollow basal part of a feather.
      1913 webster

   barrel bulk com., a measure equal to five cubic feet,
      used in estimating capacity, as of a vessel for freight.
      

   barrel drain arch., a drain in the form of a cylindrical
      tube.

   barrel of a boiler, the cylindrical part of a boiler,
      containing the flues.

   barrel of the ear anat., the tympanum, or tympanic
      cavity.

   barrel organ, an instrument for producing music by the
      action of a revolving cylinder.

   barrel vault. see under vault.
      1913 webster
see also:
barricade drum barrel bulk barrel drain barrel of a boiler barrel of the ear 
barrel organ barrel vault vault 

[3] : WordNet (r) 2.0

barrel vault
     n : the simplest form of vault; a single continuous arch

Barrel Vault >> B Words
Barrel Vault, definition of term: Barrel Vault
barrel+vault_pag1.html

Barrel >> B Words
Barrel, definition of term: Barrel
barrel_pag1.html

Vault >> V Words
Vault, definition of term: Vault
vault_pag1.html

Barrel Roll >> B Words
Barrel Roll, definition of term: Barrel Roll
barrel+roll_pag1.html

Barrel Maker >> B Words
Barrel Maker, definition of term: Barrel Maker
barrel+maker_pag1.html

Pork Barrel >> P Words
Pork Barrel, definition of term: Pork Barrel
pork+barrel_pag1.html

Gun Barrel >> G Words
Gun Barrel, definition of term: Gun Barrel
gun+barrel_pag1.html

Pole Vault >> P Words
Pole Vault, definition of term: Pole Vault
pole+vault_pag1.html

Gun Barrel City >> G Words
Gun Barrel City, definition of term: Gun Barrel City
gun+barrel+city_pag1.html