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Abacus

flat top of the capital of a column.

Abbey

main or sole church built in conjunction with an abbey

Abbey

a building inhabited by a community of monks or nuns governed by an autonomous leader

Abutment

solid masonry placed to counteract the lateral thrust of a bridge, arch, or vault.

Altar

A structure on which to place or sacrifice offerings to a deity. In a Christian church the altar is usually a stone table or slab on supports, on which the celebration of the sacrament takes place.

Alure

a passage or gallery behind a parapet at the top of a wall of a fortification.

Ambulatory

A semicircular or polygonal aisle. Often an ambulatory leads around the east end of the choir.

Apse

the semi-circular termination of the east end of the chancel or chapel.

Apsidiole

semi-circular chapel (in the transept or chancel) or secondary apse .

Arcade

A series of arches supported by columns or piers.

Arcature

series of small arcades topped by an arch.

Arch

A carved structural member that spans an opening.

Arch moulding

concentric arches set back from one another above a doorway or a window and topped by the archivolt.

Architrave

the beam which extends across the top of the columns; it forms the lowest part of the entablature.

Archivolt

set of arches rising above a doorway. In the Romanesque and gothic styles, the archivolt frames the tympanum, a richly sculpted panel.

Arms of a transept

sections of the transept on each side of the crossing.

Astragal

A small plain or ornamental moulding.

Attic

A room, usually with sloping ceilings, just beneath the roof

Avant-corps

part of a building which projects prominently from the main facade.