Abacus : Flat top of the capital of a column.
Apse : Semicircular termination or recess at the end of a church.
Architrave : In classical architecture, the beam which extends across the top of the columns; it forms the lowest part of the entablature.
Baldachin : Decorated canopy, usually over an altar.
Baptistry : Building used for the baptismal rite and containing the font. Sometimes merely a bay or chapel reserved for baptisms.
Bay : Compartment or unit of division of an interior or of a facade – usually between one window or pillar and the next.
Belvedere : Open sided structure designed to offer extensive views, normally in a formal garden.
Boss : Projection, usually carved, at the intersection of stone ribs of Gothic vaults and ceilings.
Broach spire : Octagonal spire rising from a square tower without a parapet, with pyramidal forms at the angles.
Buttress : Vertical mass of masonry built against a wall to strengthen it and to resist the outward pressure of a vault.
Campanile : Detached bell-tower, most commonly found in Italy.
Capital : Crowning feature of a column, usually carved.
Caryatid : Sculptured female figure serving as a supporting column.
Cornice : Projecting upper part of the entablature in classical architecture.
Dado : Lower part of an interior wall when panelled or painted separately from the main part.
Dome : Rounded, usually hemispherical, vault forming a roof.
Drum : Vertical, cylindrical lower part of a dome or cupola.
Entablature : In classical architecture, the beam-like division above the columns, comprising architrave, frieze and cornice.
Fleche : Slender wooden spire rising from a roof. The word is French for ‘arrow’.
Flying buttress : Arch conveying the thrust of a vault towards an isolated buttress.
Folly : Purely decorative building, without function, such as the Gothic ruins built to romanticise parks and gardens in 18th century England.
Frieze : Decorated central division of an entablature, between the architrave and the cornice.
Keystone : Central, wedge-shaped stone of an arch, so called because the arch cannot stand up until it is in position.
Lancet window : Window with a single, sharply pointed arch. The style is associated with the Early English period of Gothic architecture, around the 13th century.
Mezzanine : Low storey introduced between two loftier ones, usually the ground and first floors.
Order : Basic element of classical and Renaissance architecture, comprising the base, column, capital and entablature.
Oriel : Bay window on an upper floor, supported by projecting stonework.
Pediment : In classical architecture, the low-pitched gable above the entablature, usually filled with sculpture.
Pier : Vertical masonry support for a wall arch.
Piloti : Column on an unenclosed ground floor carrying a raised building above.
Podium : Continuous base under a building.
Rustication : Heavy stonework with a surface left rough, or with deeply channelled joints, used principally on Renaissance buildings.
Spandrel : Triangular space between the curves of two adjacent arches and the horizontal moulding above them.
Tracery : Ornamental stonework in the upper part of a Gothic window.
Tympanum : Triangular surface bounded by the mouldings of a pediment; also the space, often carved, between the lintel and arch of a Gothic doorway.
Vault : A roof or ceiling built in stone, brick or concrete, as opposed to wood.
Volute : Spiral scroll at each corner of an Ionic or Corinthian capital.
Axiom43. Architectural Terms, http://www.geocities.com/Axiom43/architecture.html. Last accessed December 13, 2009.