[wind.mill] n (14c) 1 a: a mill or machine operated by the wind usu. acting on oblique vanes or sails that radiate from a horizontal shaft; esp: a wind-driven water pump or electric generator b: the wind-driven wheel of a windmill
2: something that resembles or suggests a windmill; esp: a calisthenic exercise that involves alternately lowering each outstretched hand to touch the toes of the opposite foot 3 [fr. the episode in Don Quixote by Cervantes in which the hero attacks windmills under the illusion that they are giants]: an imaginary wrong, evil, or opponent--usu. used in the phrase to tilt at windmills
[2]windmill vt (1914): to cause to move like a windmill ~ vi: to move like a windmill; esp: to spin from the force of wind