Architectural and Engineering Glossary


Aftertack,residual Tack

The lingering tack or stickiness of a paint film which remains over a long period of time.


1.Abbr.for “above grade.”2.Abbr.for “against the grain.”


Abbr.for “American Gas Association.”


In ancient Greece,any work of art dedicated to a god.


A large central African tree with rather lightweight wood of a creamy to pinkish brown color.Used for plywood,interior millwork,and carpentry.


Abbr.for “Associated General Contractors.” 

Age Hardening

An aging process in certain metals,at room temperature,which results in increased strength and hardness.


British variant of aging.

Agglomerate Stone

See artificial stone.


The chief meeting place or marketplace in an ancient Greek city.

Agreement Form

A document setting forth in printed form the general provisions of an agreement with spaces provided for insertion of specific data relating to a particular project.

Agrément Board

See British Board of Agrément.

Agricultural Drain

Same as agricultural pipe drain.

Agricultural Lime

A hydrated lime which is used to condition soil.

Agricultural Pipe Drain.

A system of porous or perforated pipes laid in a trench filled with gravel (or the like);used for draining subsoil.


An obelisk,or the spire of a church tower.


Abbr.for “ampere-hour.”


Same as ha-ha.


Abbr.for air-handling unit.


Abbr.for “American Institute of Architects.”

AIA Uniform System

See contract documentsand uniform system.


Abbr.for “American Institute of Electrical Engineers.”


A slender form of drill used for boring or drilling a blasthole in rock.


A half gable,such as that which closes the end of a penthouse roof or of the aisle of a church.


Abbr.for “Acoustical and Insulating Materials Association.”

Aiming Angle

Same as angle of illumination;usually measured in degrees.

Air Balancing.

A procedure used to adjust the flow of air in an HVAC system so as to meet the design goals for airflow throughout the system.

Air Barrier

A membrane that acts as a resistance to air leakage.

Air Blowpipe

A pipe which emits a jet of air;used to clean an area of debris.

Air Break

In a drainage system,a piping arrangement in which a drain from an appliance,device,or fixture discharges into the open air and then into another fixture,receptacle,or interceptor;used to prevent back siphonage or backflow.

Air Brick

A perforated brick or perforated metal unit of brick size which is built into a wall;used for ventilation.

Air Chamber

In a water piping system near a valve or faucet,a vertical pipe stub which is sealed at the top and contains air;the entrapped air provides a cushion when the valve is closed suddenly,thereby eliminating the noise of water hammer.

Air Changes

A measure of the volume of air supplied to or exhausted from a building (or room);usually expressed in terms of the number of complete changes of air per hour in the room or space under consideration.

Air Cock

Same as pet cock.

Air Compressor

A machine which draws in air at atmospheric pressure,then compresses it to pressures higher than atmospheric and delivers it at a rate sufficient to operate pneumatic tools or equipment.


On drawings,abbr.for “air condition.”

Air Conditioner

A device for providing air conditioning.

Air Control Valve

Same as air maintenance device.

Air Door

Same as air curtain.

Air Drain

An empty space left around the external foundation wall of a building to prevent the earth from lying against it and causing dampness.

Air Drying

The process of drying slowly under ambient conditions of temperature and humidity,as in the natural seasoning of lumber or the hardening of paint.

Air Duct

A duct,usually fabricated of metal,fiberglass,or concrete;used to transfer air from one location to another.

Air Eliminator

In a piping system,a device used to remove air from water,steam,or a refrigerant.

Air Entraining

Descriptive of the capability of a material or process to develop a system of minute bubbles of air in cement paste,concrete,or mortar.

Air Filter

Any device used to remove solid and/or gaseous pollutants from air.

Air Grille

A type of air grating.

Air Heating System

See warm-air heating system.

Air Hole

In the foundation of a house,an opening that provides ventilation for a crawl space.

Air House

Same as pneumatic structure.

Air Line

A duct,hose,or pipe that supplies compressed air to a pneumatic tool or piece of equipment.