<B>air alert,</B><DL COMPACT><DD><B> 1. </B>a state of readiness for defense against enemy aircraft, when aircraft get into the air ready for immediate response to orders. <DD><B> 2. </B>the signal to get aircraft into the air for such defense. </DL>
<A NAME="airarm">
<B>air arm,</B> =air force.</DL>
<A NAME="airatomic">
<B>air-atomic, </B>adjective.<DL COMPACT><DD> based on or involving the use of atomic bombs carried by aircraft or of missiles armed with atomic warheads. <BR> <I>Ex. air-atomic defense.</I> </DL>
<A NAME="airattack">
<B>air attack,</B><DL COMPACT><DD> an attack by aircraft. </DL>
<A NAME="airbag">
<B>airbag, </B>noun, or <B>air bag,</B><DL COMPACT><DD> a safety device consisting of a plastic bag that inflates in front of a passenger in an automobile collision to keep him from being thrown forward. </DL>
<A NAME="airbase">
<B>air base,</B><DL COMPACT><DD> a headquarters and airfield for military aircraft. </DL>
<A NAME="airbattery">
<B>air battery,</B><DL COMPACT><DD> a battery that uses zinc or another metal as the fuel and pressurized air as the oxidizing agent. </DL>
<A NAME="airbearing">
<B>air bearing,</B><DL COMPACT><DD> a bearing using the pressure of thin jets of air to support weights, eliminate friction, etc. </DL>
<A NAME="airbed">
<B>air bed,</B><DL COMPACT><DD> (British.) an air mattress. </DL>
<A NAME="airbladder">
<B>air bladder,</B><DL COMPACT><DD> a sac in most fishes and various animals and plants that is filled with air. The air bladder of a fish is also called the <I>swim bladder</I> and adjusts the specific gravity of the fish to the water pressure at varying depths. </DL>
<A NAME="airblast">
<B>air blast,</B><DL COMPACT><DD><B> 1. </B>a stream of air, especially one produced by mechanical means. <DD><B> 2. </B>the shock caused by a very fast movement of air or of an object through the air, such as that of a missile reentering the earth's atmosphere. <DD><B> 3. </B>the downward or outward pressure wave set up by an atomic explosion in the air. </DL>
<A NAME="airboat">
<B>airboat, </B>noun.<DL COMPACT><DD> a small flat-bottomed boat driven by an airplane propeller mounted on the boat and revolving in the air, used for travel in large swamps and flooded areas. <BR> <I>Ex. Skim through the Everglades in an airboat (New Yorker).</I> </DL>
<A NAME="airborne">
<B>airborne, </B>adjective.<DL COMPACT><DD><B> 1a. </B>supported by the air; off the ground. <BR> <I>Ex. Within 15 minutes the bombers can be airborne. The kite was finally airborne.</I> <DD><B> b. </B>carried in aircraft. <BR> <I>Ex. airborne troops.</I> <DD><B> c. </B>having its aircraft in the air. <BR> <I>Ex. an airborne patrol.</I> <DD><B> 2. </B>carried by air. <BR> <I>Ex. airborne seeds, airborne contamination from industrial pollution.</I> </DL>
<A NAME="airbound">
<B>airbound, </B>adjective.<DL COMPACT><DD> stopped up by an accumulation of air, as a pipe. </DL>
<A NAME="airbrake">
<B>air brake,</B><DL COMPACT><DD><B> 1. </B>a brake or system of brakes operated by forcing compressed air against a piston or pistons. <DD><B> 2. </B><B>=speed brake.</B> </DL>
<A NAME="airbrasive">
<B>airbrasive, </B>adjective.<DL COMPACT><DD> that cleans, smooths, or cuts by the action of abrasive particles propelled at high speeds by compressed air from a nozzle. <BR> <I>Ex. an airbrasive drill.</I> </DL>
<A NAME="airbreakswitch">
<B>air-break switch,</B><DL COMPACT><DD> a switch in which an electric circuit is interrupted in the air. </DL>
<A NAME="airbreather">
<B>air-breather, </B>noun.<DL COMPACT><DD> a missile whose engine uses oxygen from the atmosphere to oxidize its fuel. </DL>
<A NAME="airbreathing">
<B>air-breathing, </B>adjective.<DL COMPACT><DD><B> 1. </B>that takes in oxygen from the atmosphere to oxidize its fuel. <BR> <I>Ex. air-breathing missiles.</I> <DD><B> 2. </B>that respirates or breathes air as a natural process. <BR> <I>Ex. air-breathing insects.</I> </DL>
<A NAME="airbrick">
<B>air brick,</B><DL COMPACT><DD> a brick perforated for ventilation. </DL>
<A NAME="airbridge">
<B>air bridge,</B><DL COMPACT><DD> a link between two or more places by aircraft. <BR> <I>Ex. Three companies have formed an air bridge between Rio and Sao Paulo, which provides nonreservation flights every half hour (London Times).</I> </DL>
<A NAME="airbrush">
<B>airbrush, </B>noun, verb.<DL COMPACT><DD><I>noun </I> a device somewhat like an atomizer, operated by compressed air, that is used to spray paint on a surface. <DD><I>v.t. </I> to paint or touch up with an airbrush. <BR> <I>Ex. The Times airbrushed out the player and printed his shadow (Time).</I> </DL>
<A NAME="airburst">
<B>airburst, </B>noun.<DL COMPACT><DD> an explosion of a bomb in the air, above the surface of the earth. <BR> <I>Ex. In a high airburst, the fireball will not touch the ground, and there will be no local fallout (Bulletin of Atomic Scientists).</I> </DL>
<A NAME="airbus">
<B>airbus, </B>noun.<DL COMPACT><DD> a very large jet aircraft for carrying passengers on short flights. </DL>
<A NAME="aircargo">
<B>air cargo,</B><DL COMPACT><DD> cargo transported by aircraft; air freight. </DL>
<A NAME="aircarrier">
<B>air carrier,</B><DL COMPACT><DD> an aircraft that carries freight. </DL>
<A NAME="aircastle">
<B>air castle,</B><DL COMPACT><DD> a daydream; castle in the air. </DL>
<A NAME="aircav">
<B>Air Cav,</B><DL COMPACT><DD> Air Cavalry. </DL>
<A NAME="aircavalry">
<B>Air Cavalry,</B><DL COMPACT><DD> a unit of the United States Army transported to combat areas by aircraft, especially helicopters. </DL>
<A NAME="aircell">
<B>air cell,</B><DL COMPACT><DD> a tiny cavity for air in an organism. The air sacs of a bird are air cells. </DL>
<A NAME="airchamber">
<B>air chamber,</B><DL COMPACT><DD> any compartment filled with air, especially a trap in a pump or other hydraulic system to prevent excessive pressures when the pump is suddenly stopped or started. </DL>
<A NAME="aircleaner">
<B>air cleaner,</B><DL COMPACT><DD> a device that removes impurities from a stream of gas or air. </DL>
<A NAME="aircoach">
<B>air coach,</B><DL COMPACT><DD> (U.S.) <DD><B> 1. </B>a class of air travel with lower fares than first class. <DD><B> 2. </B>a commercial aircraft with comparatively low fares. <DD><B> 3. </B>such aircraft collectively. </DL>
<A NAME="aircock">
<B>aircock, </B>noun.<DL COMPACT><DD> a small valve for letting air in or out. </DL>
<A NAME="aircompressor">
<B>air compressor,</B><DL COMPACT><DD> a device that pushes together, or compresses, air, and holds it under pressure, especially as a source of power for a pneumatic drill, pump, or other device. </DL>
<A NAME="aircondition">
<B>air-condition, </B>transitive verb.<DL COMPACT><DD><B> 1. </B>to supply (a building, room, car, or other enclosed area) with the equipment for air conditioning. <DD><B> 2. </B>to treat (the air within a building, car, or other enclosed area) by means of air conditioning. </DL>
<A NAME="airconditioned">
<B>air-conditioned, </B>adjective.<DL COMPACT><DD> having air conditioning. <BR> <I>Ex. In air-conditioned buildings the air is kept at the most comfortable temperature.</I> </DL>
<A NAME="airconditioner">
<B>air conditioner,</B><DL COMPACT><DD> equipment used to air-condition a building, room, car, or other enclosed area. </DL>
<A NAME="airconditioning">
<B>air conditioning,</B><DL COMPACT><DD> a means of treating air in a building, room, car, or other enclosed area, to free it from dust and to regulate its temperature and amount of moisture. <BR> <I>Ex. Air conditioning is the use of a refrigerant which is cooled by pressure changes in a condenser and cycled through a coil. Air then is blown over the cold coil (Wall Street Journal).</I> </DL>
<A NAME="aircontrol">
<B>air control,</B><DL COMPACT><DD><B> 1. </B>military control of an airspace. <DD><B> 2. </B>control of a hostile force or nation by means of a superior air or space power. <DD><B> 3. </B><B>=air traffic control.</B> </DL>
<A NAME="aircool">
<B>air-cool, </B>transitive verb.<DL COMPACT><DD><B> 1. </B>to remove heat from (an internal-combustion engine) by forcing air on or around the cylinders. <DD><B> 2. </B>to remove heat from (a room or other enclosed area) by blowing cool air in. noun <B>air-cooler.</B> </DL>
<A NAME="aircooled">
<B>air-cooled, </B>adjective.<DL COMPACT><DD> cooled by having air blown on it. </DL>
<A NAME="aircooling">
<B>air-cooling, </B>noun.<DL COMPACT><DD> the reduction of heat by passing a current of air through or over heated areas. </DL>
<A NAME="aircore">
<B>air-core, </B>adjective.<DL COMPACT><DD> (Electricity.) having a nonmetallic core. <BR> <I>Ex. an air-core transformer.</I> </DL>
<A NAME="aircored">
<B>air-cored, </B>adjective. =air-core.</DL>
<A NAME="aircorps">
<B>Air Corps,</B><DL COMPACT><DD> the air arm of the U.S. Army from 1926 to 1941, a predecessor of the U.S. Air Force. </DL>
<A NAME="aircorridor">
<B>air corridor,</B><DL COMPACT><DD> a passage or corridor over foreign-controlled territory open to aircraft as specified by government ruling or international agreement. <BR> <I>Ex. Along Western air corridors to Berlin, Soviet MIG-17s began making closeup inspections of U.S. passenger liners (Time).</I> </DL>
<A NAME="aircover">
<B>air cover,</B><DL COMPACT><DD><B> 1. </B>a force of aircraft protecting a land or sea operation, a convoy, or other group. <DD><B> 2. </B>the protection given by such a force. <BR> <I>Ex. The training of the Royal Air Force is ... to provide in daylight air cover for the craft carrying the troops and for the naval forces protecting them, and close support during the attack (Louis Mountbatten).</I> </DL>
<A NAME="aircraft">
<B>aircraft, </B>noun, pl. <B>-craft.<DL COMPACT><DD> 1. </B>an airplane, airship, helicopter, or balloon; any machine for flying in the air that is supported in flight by buoyancy (such as a balloon), or by the action of air (such as an airplane), or by reaction to one or more jet streams (such as a rocket). <DD><B> 2. </B>such machines collectively or as a class; airplanes, airships, helicopters, or balloons. <BR> <I>Ex. The rapid development of aircraft that could take off and land vertically soon might make obsolete many large airports and long runways (New York Times).</I> </DL>
