A structure, often a reinforced underground shelter designed to give protection against air raids.

(obsolete, chemistry) silicon tetrafluoride

(chemistry, obsolete) Sulfur dioxide.

(construction) A sealed airspace in a cavity wall.

plural of Air Vice Marshal

(military) The shore-based officer (aviator) responsible to the landing force commander for control and coordination of air operations within the landing force commander's area of operations when control of these operations is passed ashore.

plural of tactical air commander

(of an aircraft) Weighing more than the volume of air which it displaces. / Of, pertaining to, or using an aircraft which weighs more than the volume of air it displaces.

the air kerma per unit time.

The air force of the British armed forces