ro·​tor | \ ˈrō-tər How to pronounce rotor (audio) \

Definition of rotor

1a : a part that revolves in a stationary part a brake rotor
b : the rotating member of an electrical machine
2 : an assembly of rotating blades that supplies lift or stability for a rotorcraft

Examples of rotor in a Sentence

Recent Examples on the Web

The Osprey's tilt-rotor design further complicates this mission. Kyle Mizokami, Popular Mechanics, "Watch The Harrowing Way A Osprey Refuels in Midair," 13 Mar. 2019 Röder later invited us to touch the interior of the wheel on the brake rotor. Megan Geuss, Ars Technica, "Recuperating power: Charging a prototype Audi e-tron with kinetic energy," 7 Aug. 2018 More than 200 Ospreys — a tilt-rotor aircraft that can take off like a helicopter and fly like an airplane — are in operation with the U.S. military. Gordon Dickson, star-telegram, "Bell just got a big military aircraft contract. Will Fort Worth get any new jobs?," 12 July 2018 Nonetheless, the bulk of the companies revenues are in commercial and military helicopters and tilt-rotor aircraft. Andrew J. Hawkins, The Verge, "Uber’s ‘flying taxis’ will be built by these five aerospace companies," 8 May 2018 The standard carbon-ceramic brake rotors offer reassuringly strong stopping power for fixing misunderstood butt signals and, after a brief top-of-pedal squish zone, a firm pedal feel. Alexander Stoklosa, Car and Driver, "2018 Ferrari Portofino," 20 Feb. 2018 The helicopter unit that Mr. Shanahan managed works closely with the Pentagon, producing the Bell-Boeing V-22 Osprey tilt-rotor aircraft, seen above in 2015. Doug Cameron, WSJ, "Mattis Successor Had Long Career at Boeing," 23 Dec. 2018 The rotor blades of an attack helicopter spinning toward my virtual soldier didn’t look any more fluid or discernible between frames either. Stefan Etienne, The Verge, "MSI Oculux NXG251 monitor review: faster isn’t always better," 29 Nov. 2018 The electric power system also allows the helicopter to lose its large central blade and tail rotors while gaining a drone-like configuration of four arms that end with two counter-rotating propellers. John Timmer, Ars Technica, "Workhorse brings an electric pickup truck, helicopter to Manhattan," 19 Aug. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rotor.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of rotor

1892, in the meaning defined at sense 1a

History and Etymology for rotor

contraction of rotator

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Dictionary Entries near rotor





rotor blade


rotor disk

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Time Traveler for rotor

The first known use of rotor was in 1892

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More Definitions for rotor



English Language Learners Definition of rotor

technical : a part of a machine that turns around a central point


ro·​tor | \ ˈrō-tər How to pronounce rotor (audio) \

Kids Definition of rotor

1 : the part of an electrical machine that turns
2 : a system of spinning horizontal blades that support a helicopter in the air

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More from Merriam-Webster on rotor

Rhyming Dictionary: Words that rhyme with rotor

Spanish Central: Translation of rotor

Nglish: Translation of rotor for Spanish Speakers

Comments on rotor

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using a distributed computer network

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