Windage is a term used in aerodynamics, firearms ballistics, and automobiles that mainly relates to the effects of air (e.g., wind) on an object of interest.
In firearms parlance, the word windage refers to the sight adjustment used to compensate for the horizontal deviation of the projectile trajectory from the intended point of impact due to wind drift or Coriolis effect.
[4] The bore gap allows the shot to be loaded quickly, but reduces the efficiency of the weapon's internal ballistics, as it allows gas to leak past the projectile.
It also reduces the accuracy, as the ball takes a zig-zag path along the barrel, emerging out of the muzzle at an unpredictable angle.
[5] In automotive parlance, windage refers to parasitic drag on the crankshaft due to sump oil splashing on the crank train during rough driving, as well as dissipating energy in turbulence from the crank train moving the crankcase gas and oil mist at high RPM.