acanthus. A leaf shape, from the plant of the same name, that forms the basis for an ornament used to enrich molding and to decorate Corinthian and Composite capitals. OM-12, GL-1.

adobe. (1) Unfired brick, often containing straw, dried in the sun. GL-2. (2) The structures made from adobe brick.

aggregate. Granular material mixed with cement to form concrete, mortar, pebble dash, or terrazzo. The size of the granules may vary from sand to pebbles and is determined by the requirements of the application. FP-72, GL-3.

American bond. See bond.

American order. A variation of the Corinthian order capital with acanthus leaves replaced by corn cobs, tobacco leaves, or other regional element. CP-24.

anchor iron. An exposed, often decorative, end piece of a steel rod that connects opposing brick walls and provides structural reinforcement by pulling in the walls. WA-174.

ancon. A wedge-shaped console. CP-141, GL-4.

angle capital. Ionic capital variation that resolves a corner column by angling four volutes at 45 degrees from their traditional orientation. CP-69.

angular capital. Ionic capital variation in which all four sides, eight volutes, are angled at 45 degrees from their traditional orientation. Also called Scamozzi capital. CP-6.

anta. The end of a wall treated as a pilaster. CP-83.

antefix. The upright ornament on the peak of a gable or eave or at the ends of a roof. CR-48.

anthemion. An ornament in the shape of a cluster of leaf-like forms radiating from a central point, often used as a running repeated ornament. OM-54.

antic. An ornament in a caricature human, animal, or floral form. OM-10.

annulet. A band encircling a column. CP-68.

arcade. A passageway formed by arches on the same plane supported by columns or piers. CP-135.

architectural terracotta. Fired clay used on facades and for architectural ornament. FA-61.

archivolt. A decorative band or molding around the face of an arch. CP-147.

architrave. (1) The bottom member of an entablature, the part closest to the column. OM-107. (2) A molding around a door or window. OM-53.

ashlar. A term describing stone that has been cut and squared and the surface finished. WA-67.

astragal. A half-round molding usually composed of a string of half-globe beads or bead-and-reel shapes. Also called bead molding. OM-66.

Attic. Column base composed of molding on a plinth, in this order from top to bottom: torus, scotia, torus, plinth. CP-34.

awning window. A window that swings or pivots open from the top of the frame, keeping a horizontal orientation. WI-39.

baldachin. A canopy-like structure, often supported by columns, used to give emphasis. OM-43.

band. An ornamental molding in low relief, often with a repeated motif. OM-1.

banded. A term describing a construction, such as

bargeboard. A board, often decorated, under the eave of a gable, which seals the space between the roof and the wall. CR-79, GL-5.

base. (1) The part of a column between the bottom of the shaft and the pedestal, plinth, or ground. CP-34. (2) The bottom course of a masonry wall or the first horizontal member of a finished floor.

basket-weave. A pattern made by placing pairs of units perpendicular to adjacent pairs of similar units. WA-166.

batten door. A door built from vertical planks joined by visible top and bottom horizontal planks (battens). DW-24.

battered wall. A wall that inclines and is thicker at the base than at the top. WA-49.

bay window. A window that protrudes from the main structure of a building. WI-77.

bead-and-reel. Molding shaped in an alternating pattern of beads and convex elements (reels), often arranged as one bead to two reels. OM-64.

bead molding. A convex molding that is semicircular in section. WA-89. See also astragal.

beam. A horizontal structural element with vertical supports.

Belgian block. A rectangular stone block (usually granite) used for paving.

belt course. A horizontal band of masonry, timber, or molding of a building. WA-64.

blind. A term describing an architectural element that, for design purposes, mimics an opening such as a door or arch but is nonfunctional. GL-6.

block modillion. See modillion.

board-and-batten. Exterior siding made from adjacent vertical boards with the joints covered by narrow strips (battens) of the same material. WA-4.

bonder. See header.

bond. An arrangement of masonry units in a pattern that may be structural or purely decorative. Units that do not form a pattern are random bond. General patterns are basket-weave, diagonal bond, herringbone, running bond, stack bond. Patterns specific to brick are common (American) bond, English bond, Flemish bond. Stone patterns are coursed and random ashlar, mosaic (cobweb), coursed and uncoursed rubble. See also individual entries.

bow window. A bay window circular in plan view. See compass window.

brick. Rectangular masonry units formed of clay or shale, in a plastic state and then dried or fired. Brick nomenclature depends on the orientation of the unit: header, sailor, shiner, soldier, stretcher, rowlock. See also individual entries.

broken pediment. A pediment with a space at the top, usually a decorative shape and sometimes filled with an ornament. FA-113.

bull’s-eye window. A round or oval window, also called oeil-de-boeuf. WI-61, GL-7.

bush-hammered. A term describing a mechanically produced textured masonry finish varying from subtle to rough. WA-217.

camber. A term describing an arch or window with a shallow top curve. WA-288, CP-90.