(military) The act of using aircraft to attack an enemy to assist ground military forces.

The middle of the air, as while in flight.

To assuage a hostile situation.

Alternative spelling of airbag.

The contamination of the atmosphere by noxious gases and particulates.

Alternative spelling of airburst

A mixture of hydrogen and air used as fuel to a fuel cell. / (obsolete, chemistry) An early term for hydrogen; hydrogen gas.

(physics, meteorology) The gravity-induced downslope flow of relatively cold air. Winds thus produced are called gravity winds.

(physics, meteorology) An imaginary body of air to which may be assigned any or all of the basic dynamic and thermodynamic properties of atmospheric air. A parcel is large enough to contain a very great number of molecules, but small enough so that the properties assigned to it are approximately uniform within it and so that its motions with respect to the surrounding atmosphere do not induce marked compensatory movements. It cannot be given precise numerical definition, but a cubic foot of air might fit well into most contexts where air parcels are discussed, particularly those related to static stability.

Any recreational activity performed in flight or during freefall from a flight through the atmosphere.