any of various machines for grinding, pumping, etc., driven by the force of the wind acting upon a number of vanes or sails.
(loosely) a wind generator; wind plant.
Aeronautics. a small air turbine with blades, like those of an airplane propeller, exposed on a moving aircraft and driven by the air, used to operate gasoline pumps, radio apparatus, etc.
an imaginary opponent, wrong, etc. (in allusion to Cervantes' Don Quixote): to tilt at windmills.
verb (used with or without object)
Aeronautics. (of a propeller engine or turbojet engine) to rotate or cause to rotate solely under the force of a passing airstream.
Origin of windmill
Middle English word dating back to 1250–1300; see origin at wind1, mill1
Up next: a windmill prototype, which is a few months from being finished.
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They are, across the board, quixotic characters hacking at the windmill of language.
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He didn't mean for you to turn yourself into a windmill, that's sartin sure.'
The Depot Master|Joseph C. Lincoln
A windmill was being erected and water pipes laid scientifically.
Exit Betty|Grace Livingston Hill
"I shall have plenty of time to get back," thinks he, and down he sits under a windmill and goes off to sleep.
Old Peter's Russian Tales|Arthur Ransome
There were by this time in Virginia, glass works, a windmill, iron works.
Pioneers of the Old South|Mary Johnston
So as soon as I could get away from the shack I went 237 out to the windmill tower again.
The Prairie Mother|Arthur Stringer
British Dictionary definitions for windmill
windmill
/ (ˈwɪndˌmɪl, ˈwɪnˌmɪl) /
noun
a machine for grinding or pumping driven by a set of adjustable vanes or sails that are caused to turn by the force of the wind
the set of vanes or sails that drives such a mill
Also called: whirligigBritisha toy consisting of plastic or paper vanes attached to a stick in such a manner that they revolve like the sails of a windmillUS and Canadian name: pinwheel
an imaginary opponent or evil (esp in the phrase tilt atorfight windmills)
a small air-driven propeller fitted to a light aircraft to drive auxiliary equipmentCompare ram-air turbine
an informal name for helicopter
an informal name for propeller (def. 1)
verb
to move or cause to move like the arms of a windmill
an informal name for accommodation bill
(intr)(of an aircraft propeller, rotor of a turbine, etc) to rotate as a result of the force of a current of air rather than under power