Definition of "windmill" []

• A machine that runs on the energy generated by a wheel of adjustable blades or slats rotated by the wind. (noun)
• Something, such as a toy pinwheel, that is similar to a windmill in appearance or operation. (noun)
• To move or cause to move like the wheel of a windmill; rotate sweepingly. (verb-transitive)
• Tilt at windmills To confront and engage in conflict with an imagined opponent or threat. (idiom)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Before he was six years old, he was once discovered at the top of his father's barn, fixing up what he called a windmill of his own construction, and at another time, while he was about the same age, he attended some men fixing a pump, and observing them cut off a piece of a bored part, he procured it, and actually made a pump, with which he raised water."
• "Note the big difference in how prominent the sound of the physically identical windmill is between the two?"
• "The windmill is a machine for lifting water, turning wind power into dry land: trading energy for space, sixteenth-century style."