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

One notable win came from lightweight brake rotors and calipers. Eric Tegler, Ars Technica, "Working on this Singer 911 restoration “turns” Williams F1 engineers," 24 Aug. 2018 The company also can launch a remote four-rotor hovering drone known as a Cell on Wings, which is tethered to ground cables for data exchange and power. Christine Negroni, New York Times, "It’s Not a Bird or a Plane. It’s a 17-Foot Drone, and It’s Here to Save Your Cellphone Service.," 6 Apr. 2018 Bell has created the Autonomous Pod Transport (APT), a five-foot-tall, four-rotor drone that can deliver 10 pound packages 50 miles. Joe Pappalardo, Popular Mechanics, "The Dream of Drone Delivery Just Became Much More Real," 11 Jan. 2018 And in the case of the U.S., where rotor sizes are increasing but generator size increases aren't quite keeping pace, the ratio is dropping, very much on purpose. Avery Thompson, Popular Mechanics, "U.S. Wind Turbines Are Getting Less Powerful—and That's a Good Thing," 14 Sep. 2018 Aviation experts said that indicates the tail rotor wasn’t operating properly. Washington Post, "Tourist’s parents file lawsuit in Grand Canyon copter crash," 7 Mar. 2018 That means bigger rotors (those with a larger radius) give more thrust. Rhett Allain, WIRED, "The Physics of Launching Fireworks From a Drone," 4 July 2018 The rapid expansion of exploding gases turns the rotors, thus generating power. Matthew Jancer, Popular Mechanics, "Why Car Lovers Are So Mad for Mazda’s Rotary Engine Revival," 21 May 2018 The Smithsonian National Air & Space Museum says that Bera in the 1960s was the first woman in history to fly a helicopter with no tail rotor, as an experimental test pilot. Karen Pearlman,, "Flyovers to honor Fran Bera, 93, jet-setting aviation pioneer," 22 Mar. 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

10 Dec 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

Rhyming Dictionary: Words that rhyme with rotor

Spanish Central: Translation of rotor

Nglish: Translation of rotor for Spanish Speakers

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to enclose within walls

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