Architectural and Engineering Glossary


B Of B

Abbr.for “back of board.”


In the lumber industry,abbr.for board measure.


On drawings,abbr.for bill of materials.


In the lumber industry, abbr. for “grade B and better.”


1.On drawings, abbr. for “beams and stringers.”2.On drawings, abbr. for “bell and spigot.”3.On drawings,  abbr.for Brown and Sharpe gauge.    


1.Abbr. for “banded one side.” 2.Abbr. for “bead one side.”


Abbr. for “banded two ends.”


1.Abbr. for “banded  two  sides.” 2.Abbr. for  “bead  two  sides.” 3.Abbr.  for  “bright two sides.”


Abbr. for “banded two sides and one end.”


Abbr. for “beveled on three edges.” 


Abbr. for “beveled on four edges.”


Abbr. for “bright annealed.”

Babylonian Architecture

 In ancient Babylon, architecture characterized by: mudbrick construction; walls articulated by pilasters and recesses, sometimes faced with burnt and glazed brick; narrow rooms, mostly covered with flat timber and mud roofs; and the extensive use of bitumen in drain and  pavement  construction and as mortar.         


1.The rear, reverse, unseen, more remote, or less important part of a structure, tool, or object.2.The support for a more prominent or visible element; e.g., the back of wallboard is the surface to be plastered. 3.The top or exposed side of a slate, tile, or the like, in contrast to the bed.4.The ridge or top of a horizontal member or structure like a joist, rafter, or roof. 5.A principal rafter. 6.The extrados or top surface of an arch, often buried in the surrounding masonry.7.A low grade veneer used for the back ply in plywood construction. 8.The wainscoting below the sash frame of a window, extending to the floor.

Back Addition

The projecting rear wing of a house; an outrigger.

Back Arch

Same as arrière voussure.

Back Bedding

See back putty.

Back Check

In a hydraulic door closer, 1 a mechanism which slows the speed with which a door may be opened.     

Back Choir

Same as retrochoir.

Back Clip

A special clip, 3 attached to the back of a gypsum board; the clip fits into slots in the framing that holds the gypsum board in place. 

Back Counter

A work surface behind the front serving counter of a restaurant, usually containing short-order cooking equipment, storage cabinets, storage shelves, etc.

Back Edging

Cutting a glazed ceramic pipe by first chipping through the glaze around the perimeter and then chipping the pipe below until it is cut through.

Back Fillet

The return of the margin of a groin, doorjamb, or window jamb when it projects beyond a wall.

Back Flap, Back Fold, Back Shutter

The leaf in a window shutter that folds behind the exposed leaf of the shutter; that part of a window shutter that folds into a recess in the window casing.

Back Gutter

A gutter installed on the uphill side of a chimney on a sloping roof; used to divert water around the chimney.

Back Hearth, Inner Hearth

That part of the hearth, or floor, which is contained within the jambs of the fireplace.

Back Land

Land having no road frontage requirement. It is surrounded by land owned by others. 

Back Lining

1.A thin wood strip which lines a window casing, next to the wall and opposite the pulley stile, and provides a smooth surface for the working of the weighted sash; also called back boxing or a back jamb.2.That piece of framing forming the back recess for boxing shutters.

Back Lintel

A lintel which supports the backing of a masonry wall, as opposed to the lintel supporting the facing material.

Back Nut

1.A threaded nut, one side of which is dished to retain a grommet; used in forming a watertight pipe joint. 2.A locking nut on the shank of a pipe fitting, tap, or valve.

Back Pressure

Pressure developed in opposition to the flow of liquid or gas in a pipe, duct, conduit, etc.; due to friction, gravity, or some other restriction to flow of the conveyed fluid.

Back Propping

The placing of timbers, usually set in a diagonal or oblique position, to hold a wall in place.

Back Putty

bed glazing The bedding of glazing compound which is placed  between  the face of glass and the frame or sash containing it.

Back Shore

In raking shores, an outer member under a rider shore that temporarily supports the side of a building.

Back Siphonage

The flowing back of used,contaminated,or polluted water from a plumbing fixture or vessel into the pipe which feeds it;due to reduced pressure in the pipe.

Back Siphonage Preventer

See vacuum breaker.

Back Veneer

In veneer plywood,the layer of veneer on the side of a plywood sheet which is opposite the face veneer usually of lower quality.

Back Vent

An individual vent for a plumbing fixture located on the downstream (sewer) side of a trap,1 to protect the trap against siphonage.


To repaint a surface, which has just been painted, with a return stroke.

Back-draft Damper

A damper, 1 having blades which are actuated by gravity, permitting air to pass through them in one direction only.


To mop the back or underside of roofing felts with asphalt or tar when laying a built up roof.


Nailing the plies of a built up roof to the substrate (in addition to hot mopping) to prevent slippage.


To paint the reverse or hidden side of an object, usually for protection against the weather.

Back-to-back House

A house with a party wall at the rear as well as along the sides.


A piece of millwork used around a rectangular window or door casing to cover the gap between the casing and the wall or as a decorative feature. Also called a backbend.        


A work surface behind (and  at  the  same height as) a liquor or service bar; usually has cabinets under the work surface which are used for storage, for the display of bottles and glassware, or for refrigerated coolers.


1.Same as backband.2.At the outer edge of a metal door or window frame, the face which returns to the wall surface.


A temporary board on the outside of a scaffold.


A thin coating (such as sprayed neoprene) on the back side of a fabric to increase its durability, its resistance to the flow of air, or its heat resistance.


On the theater  stage, a large,taut, flat canvas, usually hung from the grid at the rear of the stage to mask the backstage area.