Air

1. The fluid which we breathe, and which surrounds the earth; the atmosphere. It is invisible, inodorous, insipid, transparent, compressible, elastic, and ponderable.
2. Symbolically: Something unsubstantial, light, or volatile.
3. A particular state of the atmosphere, as respects heat, cold, moisture, etc., or as affecting the sensations; as, a smoky air, a damp air, the morning air, etc.
4. Any aëriform body; a gas; as, oxygen was formerly called vital air.
5. Air in motion; a light breeze; a gentle wind.
6. Odoriferous or contaminated air.
7. That which surrounds and influences.
8. Utterance abroad; publicity; vent.
9. Intelligence; information.
10. (Mus.) The artificial motion or carriage of a horse.
1. A musical idea, or motive, rhythmically developed in consecutive single tones, so as to form a symmetrical and balanced whole, which may be sung by a single voice to the stanzas of a hymn or song, or even to plain prose, or played upon an instrument; a melody; a tune; an aria.
2. In harmonized chorals, psalmody, part songs, etc., the part which bears the tune or melody -- in modern harmony usually the upper part -- is sometimes called the air.
3. The representation or reproduction of the effect of the atmospheric medium through which every object in nature is viewed.
4. Carriage; attitude; action; movement; as, the head of that portrait has a good air.
Air balloon .
See Balloon.
Air bath
1. An apparatus for the application of air to the body.
2. An arrangement for drying substances in air of any desired temperature.
Air castle .
See Castle in the air, under Castle.
Air compressor ,
a machine for compressing air to be used as a motive power.
Air crossing ,
a passage for air in a mine.
Air cushion ,
an air-tight cushion which can be inflated; also, a device for arresting motion without shock by confined air.
Air fountain ,
a contrivance for producing a jet of water by the force of compressed air.
Air furnace ,
a furnace which depends on a natural draft and not on blast.
Air line ,
a straight line; a bee line.
Air-line , adj.;
as, air-line road.
Air lock (Hydr. Engin.),
an intermediate chamber between the outer air and the compressed-air chamber of a pneumatic caisson.
Air port (Nav.),
a scuttle or porthole in a ship to admit air.
Air spring ,
a spring in which the elasticity of air is utilized.
Air thermometer ,
a form of thermometer in which the contraction and expansion of air is made to measure changes of temperature.
Air threads ,
gossamer.
Air trap ,
a contrivance for shutting off foul air or gas from drains, sewers, etc.; a stench trap.
Air trunk ,
a pipe or shaft for conducting foul or heated air from a room.
Air valve ,
a valve to regulate the admission or egress of air; esp. a valve which opens inwardly in a steam boiler and allows air to enter.
Air way ,
a passage for a current of air; as the air way of an air pump; an air way in a mine.
In the air
1. Prevalent without traceable origin or authority, as rumors.
2. Not in a fixed or stable position; unsettled.
on the air ,
currently transmitting; live; -- used of radio and television broadcasts, to indicate that the images and sounds being picked up by cameras and microphones are being broadcast at the present moment.
To take air ,
to be divulged; to be made public.
To take the air ,
to go abroad; to walk or ride out.

1. To expose to the air for the purpose of cooling, refreshing, or purifying; to ventilate; as, to air a room.
2. To expose for the sake of public notice; to display ostentatiously; as, to air one's opinion.
3. To expose to heat, for the purpose of expelling dampness, or of warming; as, to air linen; to air liquors.