Arabesque: a fanciful, painted, modelled, or carved ornamentation, composed of plant forms, often combined with human, animal, and grotesque forms. Used by the Romans and revived by the Renaissance decorators. Also used by the Arabs—hence the name—for a flatly modelled and coloured ornament of intricate design, without human or, generally, animal forms.
Arcade: a system or range of arches, supported on columns, e.g., the range of arches and columns on each side of the nave of a cathedral or church. When used as an embellishment of exterior or interior walls, it is distinguished as Open or Blind Arcade, according as it is detached from or attached to the plane of the wall.
Arch: generally, a structure supported at the sides or ends and composed of pieces, no one of which spans the whole interval. Specifically, a structure, involving one or more curves, supported at the sides, spanning an opening and capable of supporting weight. Distinguished according to the nature of the curve as, segmental, semi-circular, ogee, pointed, horseshoe, four-centred, trefoil, cinquefoil, and multifoil. Arches, involving straight lines as well as curved, are known as “shouldered.”
Architect (pr. ar-ki-tect): lit. the master-builder.
Architectonic: possessing an architectural, or organically constructive, character. See Organic.
Architecture: the science and art of designing and constructing buildings, with a view to Utility and Beauty. See Beauty.
Architrave (lit. “principal beam”): the lowest member of an Entablature (which see); hence applied to any beam that rests on columns and carries a superstructure; also to the moulded frame which bounds the sides as well as the head of a door or window opening.
Archivolt: the mouldings around the face of an arch.
Arris: the sharp edge at which meet two flutings of a Doric Column.
Ashlar: applied to masonry of which the stones are squared and dressed with hammer or chisel.