Arabesque 
Complex and elaborate design of intertwined flowers, foliage, patterns, etc. which are painted or carved to use as ornamentation. 

Arbitration 
Dispute resolving method involving a third party decision. 

Arbor 
A latticework structure holding vines or flowers. Alternately, a treed area. 

Arbor Press 
Used to force an arbor or shaft into a hole that was bored into a material so that it can then be fastened into a lathe chuck so that the work can be turned on the lathe. 

Arboretum 
Place where different types of trees and shrubs are grown for exhibition or study. 

Arc 
Any part of a curve. Portion of a circle. Band of sparks or incandescent light formed when an electrical discharge is conducted from one electrode or conducting surface to another. 

Arc Gouging 
Use of an electric arc to shape edges of metal. 

Arc Lamp 
Light which uses an electric arc as the light source, it is also called an arc light. 

Arc Light 
Light which uses an electric arc as the light source, it is also called an arc lamp. 

Arc Strike 
Caused by a strike of an electric welding arc, it is a blemish or surface defect on metal. 

Arc Welding 
A form of metal welding done by using the heat created as an electric arc jumps from an electrode to metal. 

Arcade 
Arches mounted on a series of pillars to form a passageway or walkway. They may be open or roofed and attached to a building or detached 

Arch 
A weight bearing structure, such as over a door, which is curved rather than squared. 

Arch, Back 
Structural support for an interior or veneer wall, which is arch shaped. Exterior support is provided by a lintel. 

Arch Brick 
Wedge-shaped brick, which is normally used when building an arch. 

Arch, Gothic 
Also called a semicircular arch, parabolic arch or Tudor arch, it has a span in excess of six feet, a load capacity of over 1,000 pounds per foot, and a rise-to-span ratio greater than 0.15. 

Arch, Jack 
Also called a flat arch or straight arch, it has a horizontal or almost horizontal top surface. 

Arch, Major 
Also called a semicircular arch, parabolic arch or Tudor arch, it has a span in excess of six feet, a load capacity of over 1,000 pounds per foot, and a rise-to-span ratio greater than 0.15. 

Arch, Minor 
Arch that can support loads up to 1,000pounds per square foot and has a span of up to six feet, with a rise to span ratio of 0.15 or less. 

Arch, Parabolic
Also called a semicircular arch, parabolic arch or Tudor arch, it has a span in excess of six feet, a load capacity of over 1,000 pounds per foot, and a rise-to-span ratio greater than 0.15. 

Arch Rib
Projecting raised band or ridge along the line of an arch. 

Arch, Segmented 
Arch that can support loads up to 1,000pounds per square foot and has a span of up to six feet, with a rise to span ratio of 0.15 or less. 

Arch, Semi-Circular 
Also called a semicircular arch, parabolic arch or Tudor arch, it has a span in excess of six feet, a load capacity of over 1,000 pounds per foot, and a rise-to-span ratio greater than 0.15. 

Arch Stone 
Wedge-shaped stone, which is used in building an arch. Also called a voussoir. 

Arch Surrounds 
Decorative, half-round or elliptical trim, used above doors and windows. 

Arch, Trimmer 
Used to support a fireplace hearth, it is a low-ride brick arch. 

Arch, Tudor 
Also called a semicircular arch, parabolic arch or Tudor arch, it has a span in excess of six feet, a load capacity of over 1,000 pounds per foot, and a rise-to-span ratio greater than 0.15. 

Archway 
An arch that frames a passage. A passageway under an arch. 

Architect 
A licensed designer of homes, buildings, and other structures. 

Architect's Punch List
List of design items needing to be corrected or resolved prior to finalization of a building design. 

Architectural Fees 
The fees charged by an architect for services rendered. Charges range from per square footage, hourly or as a percentage of the projected budget. 

Architrave 
Term used to name the various parts, such as a lintel, jamb and moldings, which surround a window or door. Architrave, in classical architecture, refers to the bottom section of an establature, which is the portion of a building above a column. 

Area 
Two-dimensional, circumscribed space having measurable dimensions. Unoccupied plot of land. A building site or area around a building. 

Area Drain 
Method of collecting water runoff from an area in a receptacle. 

Area Wall 
Basement window, retaining wall, located below grade. 

Areaway 
Below grade, open space, which allows light or access to a basement door or window. 

ARES 
see American Real Estate Society. 

Argon 
Inert gas with the atomic symbol Ar, atomic number 18, and the atomic weight of 39.948. 

ARM (Adjustable Rate Mortgage) 
Loans with a periodically adjustable interest rate, reflecting the changes in a specific financial index. see also adjustable rate mortgage.

ARM Index 
The index used to adjust the interest rates on adjustable rate mortgages. T-bills or prime rate are usually used for this index, which is not controlled by individual lenders. 

Arm's Length Transaction 
Transaction between unrelated entities or individuals acting in their own interest. 

Armature 
A laminated core of conductive material, such as copper, with insulated wire wound around it, in multiple layers, in which electromotive force is produced by magnetic induction in a generator or motor; usually a revolving part, but in an alternating current machine, it is often stationery. Basically generators convert mechanical energy into electrical energy while motors convert electrical energy into mechanical energy as it rotates. They both work by electrical conductors, which pass through the lines of magnetic force and are carried on the surface of the armature. Armatures are either fixed or rotating. The field will be stationary if the armature rotates as in DC machines. The field will be rotating if the armature is stationary as in AC machines. 

Armor 
Defensive or protective covering. 

Armored Cable
Flexible, spiral wound outer covering with insulated electrical wiring inside. 

Arnott Valve 
Located at the top of a room or space, a one-way or check valve is operated by gravity, permitting the escape of air from that space. 

Arpent 
Measurement of land equal to .846625 acres (French) 

Array 
Tax assessor term describing a certain category of properties sold with a given amount of time. 

Arrears
Late or overdue payments and are in default. 

Arrester 
Wire-mesh screen protecting a fuel tank vent from flame propagation or covering an outlet to prevent sparks from escaping a heat or spark-producing source, such as an incinerator or chimney. 

Arris 
Formed edge when two surfaces join. 

Arris Fillet 
Wood strip which runs along a roof at the eave line to raise the end of the first course of shingles, tiles or other roof covering so that water will run off the edge of the roof. 

Arroyo 
Dry ravine, found in arid areas, and formed by water runoff. Not suitable for building as they are prone to flooding with significant rainfall. 

Artesian Well 
Drilled well with water rising through the opening due to naturally occurring water pressure and not using the pipe usually inserted into the outlet to control the water flow. 

Artisan 
Craftsman.