A rib vault or ribbed vault is an architectural feature for covering a wide space, such as a church nave, composed of a framework of crossed or diagonal arched ribs. Variations were used in Roman architecture, Byzantine architecture, Islamic architecture, Romanesque architecture, and especially Gothic architecture. Thin stone panels fill the space between the ribs. This greatly reduced the weight and thus the outward thrust of the vault. The ribs transmit the load downward and outward to specific points, usually rows of columns or piers. This feature allowed architects of Gothic cathedrals to make higher and thinner walls and much larger windows.
It is a type of arcuated, or arched, vault in which the severies, or panels in the bays of the vault's underside are separated from one another by ribs which conceal the groins, or the intersections of the panels. Rib vaults are, like groin vaults, formed from two or three intersecting barrel vaults; the ribs conceal the junction of the vaults.