air
n
1 the mixture of gases that forms the earth's atmosphere. At sea level dry air has a density of 1.226 kilograms per cubic metre and consists of 78.08 per cent nitrogen, 20.95 per cent oxygen, 0.93 per cent argon, 0.03 per cent carbon dioxide, with smaller quantities of ozone and inert gases; water vapour varies between 0 and 4 per cent and in industrial areas sulphur gases may be present as pollutants
2 the space above and around the earth; sky
Related adj →
aerial
4 public expression; utterance
to give air to one's complaints
5 a distinctive quality
an air of mystery
6 a person's distinctive appearance, manner, or bearing
a a simple tune for either vocal or instrumental performance
b another word for →
aria
8 transportation in aircraft (esp. in the phrase by air)
9 an archaic word for →
breath →
1--3
10 ♦
clear the air to rid a situation of tension or discord by settling misunderstandings, etc.
11 ♦
give (someone) the air
Slang to reject or dismiss (someone)
a in circulation; current
b in the process of being decided; unsettled
13 , into thin air leaving no trace behind
14 ♦
on (or off) the air (not) in the act of broadcasting or (not) being broadcast on radio or television
15 ♦
out of or from thin air suddenly and unexpectedly
16 ♦
take the air to go out of doors, as for a short walk or ride
b Informal agitated or excited
18 ♦
walk on air to feel elated or exhilarated
19 modifier (Astrology) of or relating to a group of three signs of the zodiac, Gemini, Libra, and Aquarius
Compare →
earth →
10 →
fire →
24 →
water →
12
vb
20 to expose or be exposed to the air so as to cool or freshen; ventilate
to air a room
21 to expose or be exposed to warm or heated air so as to dry
to air linen
22 tr to make known publicly; display; publicize
to air one's opinions
23 intr (of a television or radio programme) to be broadcast,
(See also)
→
airs (C13: via Old French and Latin from Greek aer the lower atmosphere)
Aïr
n a mountainous region of N central Niger, in the Sahara, rising to 1500 m (5000 ft.): a former native kingdom. Area: about 77700 sq. km (30000 sq. miles), (Also called)
Asben, Azbine
AIR
abbrev. for All India Radio
air alert
n (Military)
1 the condition in which combat aircraft are airborne and ready for an operation
2 a signal to prepare for this
air bag
n a safety device in a car, consisting of a bag that inflates automatically in an accident and prevents the passengers from being thrown forwards
air base
n a centre from which military aircraft operate, (Also called)
air station
air bed
n an inflatable mattress
air bladder
n
1 (Ichthyol) an air-filled sac, lying above the alimentary canal in bony fishes, that regulates buoyancy at different depths by a variation in the pressure of the air, (Also called)
swim bladder
2 any air-filled sac, such as one of the bladders of seaweeds
air brake
n
1 a brake operated by compressed air, esp. in heavy vehicles and trains
2 (Also called)
dive brake an articulated flap or small parachute for reducing the speed of an aircraft
3 a rotary fan or propeller connected to a shaft to reduce its speed
air bridge
n (Brit) a link by air transport between two places, esp. two places separated by a stretch of sea
air chief marshal
n a senior officer of the Royal Air Force and certain other air forces, of equivalent rank to admiral in the Royal Navy, (Abbrev.)
ACM
air cleaner
n a filter that prevents dust and other particles from entering the air-intake of an internal-combustion engine, (Also called)
air filter
air commodore
n a senior officer of the Royal Air Force and certain other air forces, of equivalent rank to brigadier in the Army
air-condition
vb tr to apply air conditioning to
air conditioning
n a system or process for controlling the temperature and sometimes the humidity and purity of the air in a house, etc.
♦
air conditioner n
air-cool
vb tr to cool (an engine) by a flow of air
Compare →
water-cool
air corridor
n an air route along which aircraft are allowed to fly
air cover
n
a the use of aircraft to provide aerial protection for ground forces against enemy air attack
b the aircraft used in this, (Also called)
air support
air curtain
n an air stream across a doorway to exclude draughts, etc.
air cushion
n
1 an inflatable cushion, usually made of rubber or plastic
2 the pocket of air that supports a hovercraft
3 a form of pneumatic suspension consisting of an enclosed volume of air
See also →
air spring
air cylinder
n a cylinder containing air, esp. one fitted with a piston and used for damping purposes
air dam
n any device, such as a spoiler, that reduces air resistance and increases the stability of a car, aircraft, etc.
air-dry
vb , -dries, -drying, -dried tr to dry by exposure to the air
air embolism
n another name for →
aeroembolism
air engine
n
1 an engine that uses the expansion of heated air to drive a piston
2 a small engine that uses compressed air to drive a piston
air-entrained concrete
n a type of concrete throughout which small air bubbles are dispersed in order to increase its frost resistance: used for making roads
air filter
n another name for →
air cleaner
air force
n
a the branch of a nation's armed services primarily responsible for air warfare
b (as modifier)
an air-force base
2 a formation in the U.S. and certain other air forces larger than an air division but smaller than an air command
air freight
n
1 freight transported by aircraft
vb
♦
air-freight
2 tr to send (goods) to their destination by aircraft
air frost
n air whose temperature is at or below 0°C
air gas
n another name for →
producer gas
air guitar
n an imaginary guitar played while miming to rock music
air gun
n a gun discharged by means of compressed air
air hardening
n a process of hardening high-alloy steels by heating and cooling in a current of air
Compare →
oil hardening
air hole
n
1 a hole that allows the passage of air, esp. for ventilation
2 a section of open water in a frozen surface
3 a less common name for →
air pocket →
1
air hostess
n a stewardess on an airliner
air-intake
n
a an opening in an aircraft through which air is drawn, esp. for the engines
b the amount of air drawn in
2 the part of a carburettor or similar device through which air enters an internal-combustion engine
3 any opening, etc., through which air enters
air jacket
n
1 an air-filled envelope or compartment surrounding a machine or part to reduce the rate at which heat is transferred to or from it
Compare →
water jacket
2 a less common name for →
life jacket
air letter
n another name for →
aerogram →
1
air-lift pump
n a pump that pumps liquid by injecting air into the lower end of an open pipe immersed in the liquid: often used in boreholes
air marshal
n
1 a senior Royal Air Force officer of equivalent rank to a vice admiral in the Royal Navy
2 a Royal Australian Air Force officer of the highest rank
3 a Royal New Zealand Air Force officer of the highest rank when chief of defence forces
air mass
n a large body of air having characteristics of temperature, moisture, and pressure that are approximately uniform horizontally
air mile
n another name for →
nautical mile →
1
Air Miles
pl n points awarded by certain companies to purchasers of flight tickets and some other products that may be used to pay for other flights
air-minded
adj interested in or promoting aviation or aircraft
♦
air-mindedness n
air miss
n a situation in which two aircraft pass very close to one another in the air; near miss
Air Officer
n a term used to denote the appointment of any officer in the Royal Air Force above the rank of Air Commodore to a position of command
air plant
n a name given to some epiphytes grown as greenhouse or house plants, esp. orchids of the large Old World tropical genus Aerides, grown for their white scented flowers spotted with red, purple, or rose
air pocket
n
1 a localized region of low air density or a descending air current, causing an aircraft to suffer an abrupt decrease in height
2 any pocket of air that prevents the flow of a liquid or gas, as in a pipe
air power
n the strength of a nation's air force
air pump
n a device for pumping air in or out of something
air raid
n
a an attack by hostile aircraft
b (as modifier)
an air-raid shelter
air-raid warden
n a member of a civil defence organization responsible for enforcing regulations, etc., during an air attack
air rifle
n a rifle discharged by compressed air
air sac
n
1 any of the membranous air-filled extensions of the lungs of birds, which increase the efficiency of gaseous exchange in the lungs
2 any of the thin-walled extensions of the tracheae of insects having a similar function
air scoop
n a device fitted to the surface of an aircraft to provide air pressure or ventilation from the airflow
Air Scout
n a scout belonging to a scout troop that specializes in flying, gliding, etc.
See →
Scout
air-sea rescue
n an air rescue at sea
air shaft
n a shaft for ventilation, esp. in a mine or tunnel
air shot
n (Golf) a shot that misses the ball completely but counts as a stroke
air sock
n another name for →
windsock
air spray
n another name for →
aerosol →
3
air spring
n (Mechanical engineering) an enclosed pocket of air used to absorb shock or sudden fluctuations of load
air station
n an airfield, usually smaller than an airport but having facilities for the maintenance of aircraft
air terminal
n (Brit) a building in a city from which air passengers are taken by road or rail to an airport
air-to-air
adj operating between aircraft in flight
air traffic
n
1 the organized movement of aircraft within a given space
2 the passengers, cargo, or mail carried by aircraft
air-traffic control
n an organization that determines the altitude, speed, and direction at which planes fly in a given area, giving instructions to pilots by radio
♦
air-traffic controller n
air turbine
n a small turbine driven by compressed air, esp. one used as a starter for engines
air valve
n
1 a device for controlling the flow of air in a pipe
2 a valve for exhausting air from a fluid system, esp. from a central-heating installation
See also →
bleed valve
air vesicle , cavity
n
1 a large air-filled intercellular space in some aquatic plants
2 a large intercellular space in a leaf into which a stoma opens
air vice-marshal
n
1 a senior Royal Air Force officer of equivalent rank to a rear admiral in the Royal Navy
2 a Royal Australian Air Force officer of the second highest rank
3 a Royal New Zealand Air Force officer of the highest rank, (Abbrev.)
AVM
air waybill
n a document made out by the consignor of goods by air freight giving details of the goods and the name of the consignee
castle in the air , in Spain
n a hope or desire unlikely to be realized; daydream
compressed air
n air at a higher pressure than atmospheric pressure: used esp. as a source of power for machines
equivalent air speed
n the speed at sea level that would produce the same Pitot-static tube reading as that measured at altitude
Fleet Air Arm
n the aviation branch of the Royal Navy, (Abbrev.)
FAA
heavier-than-air
adj
1 having a density greater than that of air
2 of or relating to an aircraft that does not depend on buoyancy for support but gains lift from aerodynamic forces
hot air
n
Informal empty and usually boastful talk
hot-air balloon
n a lighter-than-air craft in which air heated by a flame is trapped in a large fabric bag
light air
n very light air movement of force one on the Beaufort scale
lighter than air
adj lighter-than-air when prenominal
1 having a lower density than that of air
2 of or relating to an aircraft, such as a balloon or airship, that depends on buoyancy for support in the air
liquid air
n air that has been liquefied by cooling. It is a pale blue and consists mainly of liquid oxygen (boiling pt.: --182.9°C) and liquid nitrogen (boiling pt.: --195.7°C): used in the production of pure oxygen, nitrogen, and the inert gases, and as a refrigerant
Marshal of the Royal Air Force
n a rank in the Royal Air Force comparable to that of Field Marshal in the British army
off-air
adj
adv
1 obtained by reception of a radiated broadcasting signal rather than by line feed
an off-air recording
2 connected with a radio or television programme but not broadcast
an off-air phone-in
open air
n
a the place or space where the air is unenclosed; the outdoors
b (as modifier)
an open-air concert
plein-air (French)
adj of or in the manner of various French 19th-century schools of painting, esp. impressionism, concerned with the observation of light and atmosphere effects outdoors
(C19: from French phrase en plein air in the open (literally: full) air)
♦
plein-airist n
ram-air turbine
n a small air-driven turbine fitted to an aircraft to provide power in the event of a failure of the normal systems
Royal Air Force
n the air force of the United Kingdom, (Abbrev)
RAF
Royal Air Force List
n (Brit) an official list of all serving commissioned officers of the RAF and reserve officers liable for recall
Special Air Service
n a regiment in the British Army specializing in clandestine operations
surface-to-air
adj of or relating to a missile launched from the surface of the earth against airborne targets