Abacus

The topmost division of the capital of a column. See Plate 63.

Abutment Of An Arch

The mass of masonry which resists the thrust of the arch. That against which the ends of the arch rest.

Aisle

The side portion of a building, separated from the center portion usually by columns or piers.

Angle Iron

A structural iron shape whose cross section is in the form of a letter L.

Annulets

The band of small mouldings at the bottom of the Echinus of the Greek Doric capital. See Plate 64.

Antae

A pilaster attached to a wall.

Apron

The finished board placed immediately below a window stool. See Plate 49.

Arcade

A series of arches.

Architect's Scale

See page 9 and Plate 3.

Architrave of a Door or Window. The moulded finish around the opening.

Architrave of an Entablature. The lower division of the entablature. See Plate 63.

Arris

The edge formed by the intersecting of two surfaces.

Ashlar

The outside cut stone facing of a wall.

Astragal

A small moulding of circular section. See column capital of Plate 63. Also the moulding separating two doors, etc. See the sliding door of Plate 52.

Attic

That part of a classic structure that occurs above the cornice level. Also the space immediately under the roof of a house.

Back-Band

The outside member of a window or door casing. See Plate 49.

Back Hearth

That part of the hearth inside the fireplace. See Plate 61.

Backing

The inner portion of a wall.

Balcony

A platform projecting from the building wall.

Balloon Frame

See Plate 46.

Base

The lower member of a column or a building.

Base Board

The finishing board covering the plaster wall where it meets the floor.

Batten

A strip of board for use in fastening other boards together.

Batter

The slope of the face of a wall that is not plumb. See Plate 37.

Batter Boards

Boards set up at the corners of a proposed building from which are stretched the lines marking off the walls, etc.

Bay

A comparatively small projecting portion of a building. Also one division of an arcade or the space between two columns.

Beam

A large horizontal structural member supporting floors, etc.

Bond

The connection between the bricks or stones of a masonry wall formed by overlapping the pieces.

Box Frame

A window frame containing boxes for the sash weights. See Plate 49.

Bridging

A cross-bracing built between joist and studs to add stiffness to floors and walls.

Building Line

The line of the outside face of a building wall. Also the line on a lot beyond which the law forbids that a building be erected.

Building Paper

A heavy, more or less waterproof paper for use in insulating the walls, floors and roofs of buildings.

Buttress

An enlargement or projection of a wall to resist the thrust of an arch, etc.

Butts

Hinges designed to be screwed to the edge or butt of a door or window and the inside of the frame.

Camber

The convex curve of the edge of a joist or other member.

Carriage

The framing timber which is the direct support of the stair steps. See Plate 59.

Casement

A window whose frame is hinged at the side to swing out or in. See Plate 51.

Catch Basin

A simple cast iron or cement receptacle into which the water from a roof, area way, etc., will drain. It is connected with a sewer or tile drain.

Caulicoli

The stalks which spring from the second row of leaves of the Corinthian capital and extend up to form the volutes under the corners of the abacus.

Centering

The false work upon which is built masonry arches, concrete slabs, etc. In concrete work the centering is also known as the forms.

Channel

A structural steel shape.

Client

The employer of the architect. The owner who entrusts the carrying out of his building project to the designer and engineer.

Coffer

A deeply recessed panel, usually in a ceiling or dome.

Collar Beam

A horizontal timber tieing two opposite rafters together at a more or less central point of the rafters.

Colonnade

A continuous series of columns.

Console

A supporting bracket usually ornamented by a reverse scroll.

Compasses

An instrument for drawing circles.

Coped Joint

A joint between moulded pieces in which a portion of one member is cut out to receive the moulded part of the other member.

Corbel

A bracket formed on a wall by building out successive courses of masonry.

Corner Bead

A metal bead to be built into plaster corners to prevent accidental breaking off of the plaster.

Cornice

The part of a roof which projects beyond the wall. The upper main division of a classic entablature. See Plate 63.

Corona

The plane center member of a classic cornice. See Plate 63.

Court

An open space surrounded partly or entirely by a building.

Cresting

The ornamental finish of a roof ridge or the top of a wall.