A mill operated by the power of the wind, usually by the action of the wind upon oblique vanes or sails which radiate from a horizontal shaft.
- A machine that runs on the energy generated by a wheel of adjustable blades or slats rotated by the wind.
- Something, such as a toy pinwheel, that is similar to a windmill in appearance or operation.
- To move or cause to move like the wheel of a windmill; rotate sweepingly.
- tilt at windmills To confront and engage in conflict with an imagined opponent or threat.