1. a. A colorless, odorless, tasteless, gaseous mixture, mainly nitrogen (approximately 78 percent) and oxygen (approximately 21 percent) with lesser amounts of argon, carbon dioxide, hydrogen, neon, helium, and other gases. b. This mixture with varying amounts of moisture and particulate matter, enveloping Earth; the atmosphere. c. The atmosphere in an enclosure.

2. a. The sky; the firmament. b. A giant void; nothingness: The money vanished into thin air.

3. An atmospheric movement; a breeze or wind.

4. Aircraft: send troops to Europe by air.

5. a. Public utterance; vent: gave air to their grievances. b. The electronic broadcast media: "often ridiculed . . . extremist groups on air" (Christian Science Monitor).

6. A peculiar or characteristic impression; an aura.

7. Personal bearing, appearance, or manner; mien.

8. airs An affected, often haughty pose; affectation. See synonyms at affectation.

9. Music. A melody or tune, especially: a. The soprano or treble part in a harmonized composition. b. A solo with or without accompaniment.

10. Air conditioning.

11. Archaic. Breath.

1. To expose so that air can dry, cool, or freshen; ventilate.

2. To give vent to publicly: airing my pet peeves. See synonyms at vent1.

3. To broadcast on television or radio: "The ad was submitted to CBS . . . which accepted and aired it" (New York).