rotor
Americannoun
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Electricity. a rotating member of a machine.
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Aeronautics. a system of rotating airfoils, as the horizontal ones of a helicopter or of the compressor of a jet engine.
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any of a number of tall, cylindrical devices mounted on a special ship rotor ship and rotated in such a way that the Magnus effect of wind impinging on the cylinders is used to drive and maneuver the vessel.
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(in a self-winding watch) a weight eccentrically mounted on an arbor for keeping the mainspring wound.
noun
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the rotating member of a machine or device, esp the armature of a motor or generator or the rotating assembly of a turbine Compare stator
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a device having blades radiating from a central hub that is rotated to produce thrust to lift and propel a helicopter
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the revolving arm of the distributor of an internal-combustion engine
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a violent rolling wave of air occurring in the lee of a mountain or hill, in which the air rotates about a horizontal axis
Other Word Forms
Noun Inflected Forms
Etymology
Origin of rotor
First recorded in 1873; short for rotator
Vocabulary lists containing rotor
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Investigators last year examined whether problems with the helicopter’s composite rotor blades contributed to the aircraft’s crash near New York City, The Wall Street Journal previously reported.
From The Wall Street Journal ● Jul. 16, 2026
Video of the incident emerged showing the cockpit apparently becoming detached from the rotor.
From Barron's ● Jul. 16, 2026
Videos posted on Facebook from Long Beach also showed flashes and bangs in neighborhoods, and the loud rotor of a helicopter overhead.
From Los Angeles Times ● Jun. 6, 2026
Carmakers including BMW and Renault have developed EV motors that work in the same way, using carbon-graphite brushes that slide against the rotor to feed it electricity.
From The Wall Street Journal ● Jun. 2, 2026
The rotor croaked like a stepped-on frog, but dang—pretty impressive for a rush job.
From "The House of Hades" by Rick Riordan
"By changing the distance between the magnetic layers, we could drive the system into a regime of competing interactions where the rotors constantly reorganize as they slide," says Hongri Gu, who carried out the experiments.
From Science Daily ● Mar. 22, 2026
As the light show unfolded, the lantern's blindingly bright facades concealed a flurry of activity behind, as teams of people turned large metal barrels called rotors by hand to produce a kaleidoscopic effect.
From Barron's ● Dec. 19, 2025
Unlike tilt-rotor designs, the rotors here are fixed; the BlackFly takes off and lands propulsively by rotation of the entire craft.
From The Wall Street Journal ● Oct. 17, 2025
The technology, known as Flettner rotors, were designed by aeronautical engineers led by the German inventor Anton Flettner.
From BBC ● Oct. 13, 2025
I touch my ear, grateful for the clattering of the rotors.
From "The Bletchley Riddle" by Ruta Sepetys and Steve Sheinkin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
