windage

(noun) the retarding force of air friction on a moving object.

(noun) the space between the projectile of a smoothbore gun and the surface of the bore of the gun.

(noun) exposure to the wind (as the exposed part of a vessel's hull which is responsible for wind resistance). Synonyms: wind exposure.

(noun) the deflection of a projectile resulting from the effects of wind. Synonyms: wind deflection.