Barrel , Cradle , Cylindrical , ∨ Wagon , vault Meaning, Definition & Usage

Definitions
  1. (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.

Webster 1913