ro·tor | \ˈrō-tər \

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

Any lubricant on the threads may allow them to be overtightened, which could damage the brake rotor. Bob Weber,, "Want better air circulation? Bring back the vent window," 20 May 2018 The brakes are all business with 15.7-inch ventilated front rotors and six-piston aluminum calipers; 14.1-inch ventilated discs and four-piston clampers bring up the rear. Jeff Yip, Houston Chronicle, "Stunning LEXUS LC 500H Grand Tourer pushes the envelope," 23 Feb. 2018 With counter-rotating rotors, sometimes helicopters can go faster. David Grossman, Popular Mechanics, "Why Aren't Helicopters Faster?," 9 Feb. 2018 For disc brakes that means pads and rotors, and for drum brakes that means shoes and drums. Matt Jancer, Popular Mechanics, "How To Resurrect a Sleeping Car," 7 Feb. 2018 The brake fluid is OK, the pads and rotors almost new. Bob Weber,, "Burning smell is most likely from oil leak," 16 July 2017 Drones come in many forms, from tiny quad-rotor copter toys to missile-firing winged planes, or even 7-ton aircraft that can stay aloft for 34 hours at a stretch. Jeremy Straub, Smithsonian, "Would You Trust Drone Software to Pilot Your Flight?," 20 Apr. 2018 Video taken by a bystander and posted on Twitter shows the helicopter, a private charter hired for a photo shoot, land hard in the water and then capsize, its rotors slapping at the water. USA TODAY, "Helicopter crash pilot issued mayday before NYC crash," 12 Mar. 2018 So the rotors push the air down and increase the air-momentum. Rhett Allain, WIRED, "The Physics of Launching Fireworks From a Drone," 4 July 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

Statistics for rotor

Last Updated

15 Oct 2018

Look-up Popularity

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

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


ro·tor | \ˈrō-tər \

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

See words that rhyme with rotor

Spanish Central: Translation of rotor

Nglish: Translation of rotor for Spanish Speakers

Comments on rotor

What made you want to look up rotor? Please tell us where you read or heard it (including the quote, if possible).


to reject or criticize sharply

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