Glossary
A. Pillar: A support which does not taper, has an impost, and does not need to be cylindrical as is the case with a column. The shaft consists of either rectangular, octagonal, circular, or cruciform blocks and may have a capital.
B. Capital: Architectural element that surmounts a column or any other vertical support.
C. Keystone: Stone in the form of wedge forming the central element of a lintel, vault, or arch. Pendant keystones are found at the intersection of ribbed vaults. Originally from the Latin clavis for "key."
D. Vaulting: A curved, self supporting wall or ceiling that covers a space between two walls and rests on pillars. Romanesque antecedents of the Gothic ribbed vault are the barrel vault and the groined vault. The ribbed vault is composed of diagonally arched ribs and can be classified as tri-partite, quatri-partite, or sexpartite. Sexpartite vaults have an additional transversal rib in the center of the bay.