atmospheric pressure or barometric pressure. / the (amount of) pressure of air within something

(military) A ground-based anti-aircraft missile.

(military) A missile that is fired from an aircraft to attack another aircraft.

plural of aid

Third-person singular simple present indicative form of aid

A region's air supply. / The region supplied by a source of air.

Alternative form of airshaft

(aviation, of an act or action) With the participants being two or more aircraft in flight. / (aviation, military, of a missile) Fired from an aircraft in flight at another one.

(of a missile) fired from the ground at an aircraft in flight, or at an incoming missile

(of a missile) fired from the ground, or from a ship, at an aircraft in flight, or at an incoming missile