n. The disturbance of the atmosphere by the movement of any object through it, as by that of a revolving fly-wheel or armature.n. The space intervening between the moving part of any mechanism and the inclosure within which it moves, as the air-gap of a dynamo.n. The air-friction of the moving parts of a machine as distinguished from the friction of the bearing surfaces.n. In gunnery:n. The difference allowed between the diameter of a projectile and that of the bore of the gun from which it is to be fired, in order to allow the escape of some part of the explosive gas, and to prevent too great friction.n. The rush or concussion of the air produced by the rapid passage of a shot.n. The influence of the wind in deflecting a missile, as a ball or an arrow, from its direct path, or aside from the point or object at which it is aimed; also, the amount or extent of such deflection.n. The play between the spindle of the De Bange gas-cheek and its cavity in the breech-screw: it is expressed in decimal parts of an inch, and is measured by the difference between the diameters of the spindle and its cavity.n. In surgery, same as wind-contusion.