WINDMILL

A machine which translates linear motion of wind to rotational motion by means of adjustable vanes called sails.

The structure containing such machinery.

A child's toy consisting of vanes mounted on a stick that rotate when blown by a person or by the wind.

To rotate with a sweeping motion.

"She ran down the hill, windmilling her arms with glee."

Of a rotating part of a machine, to (become disengaged and) rotate freely.

"The axle broke and the wheel windmilled in place briefly before careening through the wall."