Atmospheric Pressure 
Pressure due to the weight of the earth's atmosphere, equal at sea level to about 14.69 lbs. per square inch. 

Atom 
Any of the indivisible particles claimed to be the basic component of all matters. 

Atomize
To separate into atoms. To reduce a liquid into a fine spray. To disintegrate. 

At-risk Rules 
Rulings that losses can only be deducted for tax purposes to the degree of risk and are restricted to the cash investment and debt for which the taxpayer is personally liable. 

Atrium 
A large area, which forms a courtyard within a building; often enclosed in glass and open to sunlight and may be several stories high. 

Attached Column 
Column that has three quarters of its diameter projecting from a wall. 

Attached Garage 
Garage that is part of the same building as the dwelling. 

Attachment 
Legal term, which authorizes the holder of a Writ in the taking of property of rights because of legal action. The purpose is to satisfy a judgment. 

Attenuator 
Electrical device used to vary signal strength. 

Attest 
Statement that provides an objective evaluation of a real estate company's financial statement to aid financial statement users. 

Attestation Clause 
Provision at the end of a document showing signatures of witnesses to the fact that the document was executed in their presence. 

Attic 
Space between the ceiling joists and roof rafters of a structure. An attic may be accessible by a staircase or other means and may also finished into rooms. 

Attic Fan 
Fan used to remove hot air, thus cooling the area. 

Attic Ventilator 
Slotted or screened opening that allows air to flow into attic space. 

Attorney-at-Law 
Individual who has been admitted to the bar and allowed to practice law in his/her state and may perform all the services necessary to represent clients. 

Attorney of Record 
Attorney whose name appears official in the permanent records of a case. 

Attornment 
Agreement by a tenant to accept a replacement landlord. 

Attractive Nuisance 
Condition on property that may be attractive but hazardous to children. The property owner must take responsibility to prevent children from having access, which may put them in danger. 

Attribution 
Constructive ownership - where the tax law assigns to one taxpayer the ownership interest of another taxpayer. 

Auction Market 
Where property is sold to the highest bidder and the last & best bid price is accepted by the auctioneer announcing, "sold". 

Audible 
Generally accepted as being from 20Hz to 20kHz, audible refers to being within the range of normal hearing. 

Audio 
Of hearing or sound. 

Audio Frequency
Within the range of human hearing. 

Audit 
Examination of financial records of a business or individual to uncover irregularities or errors. 

Auditorium
A large room or hall used for the gathering of an audience. 

Auger 
Spiral-shaped tool for boring holes in wood. Also a drill bit. 

Austenite
A crystalline structure of steel, which contains elements, like carbon, in solid solution, and formed under temperatures of between 1670 and 2535 degrees Fahrenheit. 

Autecology 
The ecological study of a single organism or a single species of organism. 

Auto 
Prefix meaning self. 

Autogenous Healing 
The filling in of masonry cracks by a natural process, occurring over a long period of time. 

Autogenous Weld 
Weld made without any additional filler metal. 

Automatic 
Involuntary or reflexive. Self-regulating. 

Automatic Flue Damper 
Device in the flue of a heating unit that closes, when not in use, to prevent heat loss. 

Automatic Level 
Transit that uses a suspended compensator to automatically maintain a set level. 

Automatic Renewal Clause
Provision in an agreement, which allows renewal at the end of its initial term, such as a lease. 

Automatic Sprinkler System 
Fire protection system, required in some types of buildings, which is activated automatically by intense heat. 

Automatic Vent Damper 
Vent damper that will open when there is a small air flow and close when there is none. 

Automatic Welding 
Method using machine-controlled welding wire feed and weld head movement. 

Autotransformer 
Transformer with at least part of the windings common to both the primary and secondary circuits, with very low losses. It may be used to change electric voltage from a generator to the higher voltage needed for efficient transmission over power lines. They can also be used to change a two-wire electrical supply to a three-wire system. 

Auxiliary 
Additional; supplemental; acting in a subordinate manner. 

Auxiliary Hoist 
Additional crane hoist to assist the main hoist. 

Auxiliary Lane 
Secondary pathway. 

Average Office Occupancy 
Average number of business days an office is in use. 

Average Price 
Price of a home, as figured by totaling the sales prices of the houses sold in an area, and dividing that number by the number of homes. 

Avigation 
Aerial navigation that might interfere with the use by the property owner by creating undue noise and may also reduce the value of the land. 

Avigation Easement 
Easement over private property, near an airport, limiting the height of structures or trees. 

Avoirdupois Weight 
System of weights based on 1 pound equaling 16 ounces and an ounce equaling 16 drams. 

Avonite 
Solid-surface material that has a textured granite or gemstone look. Avonite resembles stone, with the color being the same through the material. It is a popular material for use in baths and kitchens since it can be worked and polished with woodworking tools. 

Avulsion 
Removal of land by the action of water erosion. 

AWG 
see American Wire Gauge. 

Awning 
Roof-like cover that provides shelter from the elements. 

Awning Windows 
Single-sash windows that tilt outward and up with the sash hinged at the top, it swings open from the bottom. 

Axe 
Tool for chopping trees and splitting wood, it has a long wooden handle with a metal head with either a single or double-sided blade 

Axes 
Plural of axis. 

Axial 
Around, on or along the axis of an object.

Axial Growth 
Land expansion resembling a star with the center being the city. 

Axis 
Real or imaginary straight line on which an object rotates or appears to rotate; a real or imaginary straight line around which the parts of a thing are symmetrically or evenly arranged or composed. 

Axle 
A rod on which a wheel turns or one connected to a wheel so that they turn together; a bar connecting two opposite wheels. 

Axle, Fixed 
An axle that does not rotate. 

Axle, Rotating 
Axle rotating on bearings but fixed at the wheel. 

Azimuth 
Angle from north or south of a property and is looked at clockwise from the north by a real estate appraiser.