windage

The effect of wind on the course of a projectile.

The point or degree at which the wind gauge or sight of a rifle or gun must be set to compensate for the effect of the wind.

The difference in a given firearm between the diameter of the projectile fired and the diameter of the bore of the firearm.

The disturbance of air caused by the passage of a fast-moving object, such as a railway train.

The part of the surface of a ship exposed to the wind.

In gunnery:

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.

The rush or concussion of the air produced by the rapid passage of a shot.

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.