Acanthus 
Architectural ornament in the shape of the acanthus leaf. 

Accelerated cost recovery system 
A tax calculation to provide greater depreciation during early years of ownership of property or real estate, mandated by the Tax Reform Act of 1986. 

Accelerated depreciation 
Bookkeeping methods to depreciate property more quickly in the early years of ownership. 

Acceleration Clause 
A provision in some loans, which gives the lender the right to collect the full balance of that loan, if the borrower misses a payment. 

Acceleration Loss 
Energy used in an air-moving system to accelerate the air to the required velocity. 

Accelerator 
Substance that shortens the setting times of concrete and mortar. Accelerators, or accelerants, are added in cold weather when there is a danger of the concrete or mortar freezing before it can cure properly. Accelerators are considered admixtures. Chemical substance added to a mixture to speed up a reaction. 

Accelerometer 
Instrument that measures acceleration. It is attached to the surface of the object that will experience the acceleration. As the object moves, it causes an electric current to flow, which measures the amount of acceleration that is taking place and indicates that amount on the calibrated accelerometer. 

Acceptable 
Satisfactory. 

Acceptance 
Written approval, made by the seller, of acceptance of an offer made by a potential buyer 

Access 
A means of entering a property or building. Ability to reach something. 

Access Court 
Open area onto which the exits from two or more buildings lead. 

Access Panel 
Removable panel that permits entry to an area that is normally sealed. 

Access Right 
The right of a property owner to go to and return from an adjoining street without interference. 

Accessible 
Within reach. 

Accessibility 
Measurement of how much access of a building can be obtained by handicapped people. 

Accession 
The right of an owner to have the advantages of property ownership, which include air rights, mineral rights, riparian rights, and rights to alluvion, and manmade improvements. Acquisition of additional property by growth or increase in the existing property. It can be a natural process, such as a changing river course adding land or through the purchase of adjacent land. 

Accessory
Device that supplements the usefulness of a system or machine. Natural feature, such as a rock formation, used as a reference point in surveying. 

Accessory Building 
Building which is secondary to the main structure on the same piece of property such as a shed or garage. 

Accident 
Unplanned event. Small but distinct surface irregularity in land. 

Accolade
Molding or decoration with the approximate shape of an ogee cut in the flat surface of an arch or lintel. An ogee is an S-shaped curve on a surface formed by a convex and concave surface curve joined together. 

Accordion Door 
Type of door that is pleated into many vertical folds and supported by rollers inserted in a track at the top. As it is closed, the fold of the door resembles the bellows of an accordion. 

Account 
Record of financial transactions. Credit extended. Commercial relationship involving credit. A customer. A financial fund. 

Accountant 
Person who specializes in keeping, inspecting and adjusting financial records. 

Accounts Payable
Money owed to someone else. 

Accounts Receivable 
Money owed to you. 

Accouple 
To join together. 

Accouplement
Timber brace or a tie of timber between two structural members. Pairs of columns placed close together. 

Accretion 
Natural process of adding soil to land, such as by water action which leaves earth or sand deposits. This is possible through flooding, storms, etc. Natural soil accretions belong to the property owner. 

Accrual 
The recognition of revenue when earned or expenses when incurred regardless of when cash is received or disbursed. 

Accrual Accounting 
Recording income as accounts receivable when earned and recording debts as accounts payable when they are incurred. Also called accrual basis accounting. 

Accrual Basis 
Recording income as accounts receivable when earned and recording debts as accounts payable when they are incurred. Also called accrual basis accounting. 

Accrue 
To accumulate or be added periodically. To come about as a natural growth. To become enforceable. To increase. 

Accumulator 
Storage chamber for gas pressure. The accumulator contains pressurized gas, which can be fed into the item to which it is connected, such as a hydraulic or pneumatic system. The energy produced by the release of the gas serves as a motive force in the system to do the work, such as moving the fluid or actuating a valve. 

Accuracy 
Correctness. In conformation with a standard. 

Accurate 
Without error. Conforming to a standard. 

Accusation 
Charge of improper conduct. 

Acetate 
A salt or ester of acetic acid used in the manufacture of such products as synthetic fibers and plastics. 

Acetic Acid 
A colorless acid which is the essential part of vinegar; it is used in the production of synthetic materials and solvents. 

Acetone 
Volatile solvent often used for cleaning. 

Acetylene 
A hydrocarbon gas used in welding and flame-cutting operations; it generates high heat when used with gaseous oxygen under pressure. 

Acid 
Sour tasting compound that can chemically neutralize bases. Muriatic acid is commonly added to swimming pools to inhibit algae growth and to keep the water PH-balanced. 

Acid Brick 
Chemical-resistant brick made from hard-burned shale, often used as flooring in areas where chemical spills are likely to occur. 

Acid Cleaning 
Washing concrete with a 5 to 10 percent solution of muriatic acid to clean it, which can be done after the concrete has cured for at least two weeks. 

Acid-core Solder 
Solder with an acid core designed solely for soldering metal together in non-electric applications, such as joining pieces of flashing together. 

Acknowledgment 
Declaration, in writing, that a person has acted voluntarily and is usually verified by an authorized official. 

Acoustic 
Pertaining to hearing or sound. Relating to music not electronically amplified. 

Acoustic Impedance 
Indicator of the ability of a material to transmit sound. 

Acoustic Ohm 
Unit used to measure a material's ability to resist the transmission of sound. 

Acoustic Reactance 
Resistance to the passage of sound through a medium, either solid, liquid or gas. It is caused by the internal and elastic properties of the medium, which allows it to absorb the sound. 

Acoustic Resistance 
Resistance to the passage of sound through a substance or medium caused by internal friction of the medium. 

Acoustical Board 
Any rigid material that attenuates or absorbs sound. 

Acoustical Ceiling Coating 
Rough, decorative coating, sometimes called popcorn because of its appearance. Coating is sprayed on to acoustical board to aid in the reduction of reflected sound. Acoustical ceiling coating applied over drywall has less sound damping properties, but requires less drywall preparation than other textures, offering both time, labor and cost savings. 

Acoustical Cloud 
Acoustically reflective panels used in concert halls to control the sonic properties of the hall. 

Acoustical Material 
Sound-absorbing material usually applied to walls or ceilings, including sound-absorbing tiles, cork, wood, etc. 

Acoustical Plaster 
Plaster that is mixed with a sound-absorbing material. 

Acoustical Tiles 
Tiles that reduce sound within a room. Achieving soundproofing between rooms, requires installationof other materials, such as heavy drywall and insulation. Acoustical tile, as well as other acoustical material, lowers sound within a room by absorbing it. 

Acquest 
To acquire property through purchase. 

Acquiescence 
Accepting or complying without objection, thus implying the waiver of the right to legal action. 

Acquisition 
The securing of ownership or controlling interest in a property or other object through either purchase or a merger. 

Acquisition Loan 
Money borrowed for the sole purpose of purchasing property. 

Acre 
Land measurement equaling 43,560 square feet. 

Acre-foot 
Volume of material required to cover an acre of land to a depth of one foot. 

Acroter 
Small pedestal for a statue; the statue on such a pedestal. 

Acroterium
Small pedestal for a statue; the statue on such a pedestal. 

Acrylic Plastic 
Noncrystalline thermoplastic that is clear, weather and shatter resistant. 

Acrylic Resin 
Thermoplastic resin. 

Acrylic Resin Synthetic
Resin used as a bonding agent or sealer in concrete construction. 

Act of God 
Action occurring without the intervention of man which could include but not be limited to hurricanes,earthquakes, floods, lightening, etc. 

Action
A procedure brought before a court, in the form of a complaint, to demand a legal right, which in real estate would be to repossess or regain certain properties or hereditaments. An action based on the right of possession is termed possessory and a property right action is termed droitural. 

Action in Personam 
Judicial proceeding against a person rather than against the property of that person. It would seek to have that person uphold the terms of a contract, make up for a loss or provide a service. In common law, it seeks the payment for a debt or damages incurred. 

Action in Rem 
Judicial proceedings against property, literally "against the thing". While in legal theory an action in rem occurs only against property, in actuality it consists of a legal action between parties for the purpose of attaching or disposing of property owned by them. 

Actionable 
Affording grounds for a lawsuit. 

Activate 
To speed up a reaction, such as the curing of concrete or the solidifying of epoxy. To put in motion. To make something more reactive. 

Activator 
Substance that acts as a catalyst, speeding up a chemical reaction without being affected by the reaction. 

Active 
Energetic. Engaged in present operation or movement. Requiring a power input to operate. 

Active Participation 
Involvement in real estate ownership and management on a continuing basis as contrasted to passive participation. Tax laws provide greater tax benefits when the owner actively participates in real estate property and rentals. 

Active Solar Heater 
Mechanical system for collecting solar energy. The water is heated in solar collectors, then stored in tanks for distribution within the building. 

Active Solar System 
Transfer of solar energy, for storage or direct use, by utilization of fans or electric pumps. 

Actual Age
Number of years that a building has been standing. 

Actual Notice 
Direct knowledge, by a purchaser, of the terms of a property transaction, including all details in the public record relating to the title; liens, surveys, access, air rights, mineral rights, water rights, etc. Actual notice is either express or implied. Express notice has established that the purchaser was shown all the relevant details. Implied assumes that the purchaser's knowledge was sufficient to institute investigation and inquiry. 

Actual Size 
The actual size of a piece of material, as opposed to its nominal size. Boards and timbers are one size when "rough", and smaller after milling or finishing. For example, a 2' X 4" nominal size is only 1-½" X 3-½" actual size. Brick and block also have actual sizes different from their nominal size. With many other materials, the nominal size is the same as the actual. A 4' X 8" sheet of plywood, for example, is exactly that. 

Actuator 
Device for moving or controlling something indirectly, such as an air actuator used to remotely open or close a valve. 

ACW
see Air Acetylene Welding.