BAY n.
, or other part of a building, or of the whole building, as marked off by the buttresses, vaulting, mullions of a window, etc.; one of the main divisions of any structure, as the part of a bridge between two piers.
FAN n.
See Scallop, n., 1. -- Fan tracery (Arch.), the decorative tracery on the surface of fan vaulting. -- Fan vaulting (Arch.), an elaborate system of vaulting, in which the ribs diverge somewhat like the rays of a fan, as in Henry VII.'s chapel in Westminster Abbey. It is peculiar to English Gothic. -- Fan wheel, the w…
RIB n.
In Gothic vaulting, one of the primary members of the vault. These are strong arches, meeting and crossing one another, dividing the whole space into triangles, which are then filled by vaulted construction of lighter material. Hence, an imitation of one of these in wood, plaster, or the like.