A masonry roof or ceiling constructed on the arch principle. A barrel or tunnel vault, semi-cylindrical in cross-section, is in effect a deep arch or an uninterrupted series of arches, one behind the other, over an oblong space. A quadrant vault is a half-barrel vault. A groin or cross vault is formed at the point at which two barrel vaults intersect at right angles. In a ribbed vault, there is a framework of ribs or arches under the intersections of the vaulting sections. A sexpartite vault is a vault whose ribs divide the vault into six compartments. A fan vault is a vault characteristic of English Perpendicular Gothic, in which radiating ribs form a fanlike pattern.