Abacus

DEFINITION

In architecture, a flat slab on top of a capital, beneath an architrave. Also called an impost block.Example: An abacus as part of a schematic diagram of the Doric order.Also see capital, column, classical orders, cornice, Corinthian, Doric, echinus, entablature, frieze, Ionic, metope, orders, shaft, and stylobate.