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 wide rubber enhances stopping power from the large four-wheel vented disc brakes, with 13.3-inch front rotors and 13-inch rear. Mark Maynard, San Diego Union-Tribune, "2019 Audi A7 Sportback: a continental grand tourer," 26 July 2019 This means Dragonfly's rotors should be able to fly the vehicle around with relative ease. Eric Berger, Ars Technica, "NASA will fund a revolutionary mission to fly through Titan’s atmosphere," 27 June 2019 The two rotors, which spin in opposite directions for stability, turn at 2,800 rpm, up to 10 times the speed of an ordinary helicopter. Jonathon Keats, Discover Magazine, "The Origins of Flight, From Birds to Bugs to Planes," 21 June 2019 This fuselage is packed with rechargeable lithium-ion batteries that not only turn the two mighty rotors, but also provide heat to protect the copter’s electronics when nighttime temperatures dip to minus 130 degrees Fahrenheit. Jonathon Keats, Discover Magazine, "The Origins of Flight, From Birds to Bugs to Planes," 21 June 2019 Specifically, Kaman may accelerate investment in the unmanned K-MAX helicopter platform and new composite rotor blades, Keating said. Stephen Singer,, "Kaman to sell distribution business for $700M and focus on booming aviation markets," 26 June 2019 Electric motors, whether AC or DC, work by causing a magnetic field in the rotating part (rotor) to interact with a magnetic field in the stationary part (stator) of the machine. The Economist, "Do electric cars dream of software fixes?," 22 Apr. 2018 Two years before that, in July 2007, a Liberty sightseeing chopper carrying eight people suffered a rotor blade separation midflight and crashed into the Hudson River. Emanuella Grinberg, CNN, "Deadly helicopter crash renews calls to ban flights over Manhattan," 10 June 2019 In 1977, four people waiting on the roof were killed when a helicopter toppled over and a rotor blade broke off and hit them. Jim Mustian, Twin Cities, "Helicopter crashes on roof of NYC skyscraper; pilot killed," 10 June 2019

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

6 Aug 2019

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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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of or relating to the heavens

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