re·​ac·​tor | \ rē-ˈak-tər How to pronounce reactor (audio) \

Definition of reactor

1 : one that reacts
2 : a device (such as a coil, winding, or conductor of small resistance) used to introduce reactance into an alternating-current circuit
3a : a vat for an industrial chemical reaction
b : a device for the controlled release of nuclear energy (as for producing heat)

Examples of reactor in a Sentence

Recent Examples on the Web Westinghouse lost out on a contract to build a new reactor in Hungary when Russia offered the Hungarian prime minister, Viktor Orban, a loan of $11 billion. New York Times, "Coming to a Country Near You: A Russian Nuclear Power Plant," 21 Mar. 2020 President Barack Obama announced more than $8 billion in new federal loan guarantees to build two nuclear reactors in Georgia., "This day in history," 16 Feb. 2020 Energy Northwest already operates the only commercial nuclear power reactor in the Northwest, Columbia Generating Station near Richland, in addition to small solar and hydroelectric projects and a wind farm. USA TODAY, "Tibetan monks at turtle release, puppy rescue 911: News from around our 50 states," 3 Feb. 2020 Opened in August 2010, Bushehr is not only Iran's first nuclear plant but the first civilian reactor in the Middle East. Artemis Moshtaghian, CNN, "Two earthquakes strike near Iran nuclear plant," 8 Jan. 2020 Soon after, all 54 reactors in Japan were shut down amid safety fears, winking out nearly 50 gigawatts of generating capacity. The Economist, "Was shutting Japan’s reactors deadlier than the Fukushima disaster?," 7 Nov. 2019 Starring Jared Harris as a scientist determined to get to the bottom of the 1986 explosion of a nuclear reactor in Soviet Ukraine, the drama focuses as much on the political fallout as the nuclear one. Los Angeles Times, "Commentary: Fantasy collides with reality as Emmy voters reward ‘Thrones,’ rebuke Trump," 16 July 2019 Tehran also operates an over 50-year-old research reactor in Tehran. Fox News, "AP EXPLAINS: Iran's nuclear program as 2015 deal unravels," 17 June 2019 Malmstadt says the team has a paper under peer review that demonstrates their control of 16 of these reactors working in tandem. Daniel Oberhaus, Wired, "Cheap Nanoparticles Pave the Way for Carbon-Neutral Fuel," 19 Feb. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'reactor.' 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 reactor

1890, in the meaning defined at sense 1

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Time Traveler for reactor

Time Traveler

The first known use of reactor was in 1890

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Last Updated

25 Mar 2020

Cite this Entry

“Reactor.” Dictionary, Merriam-Webster, Accessed 29 Mar. 2020.

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More Definitions for reactor


How to pronounce reactor (audio)

English Language Learners Definition of reactor

physics : a large device that produces nuclear energy


re·​ac·​tor | \ rē-ˈak-tər How to pronounce reactor (audio) \

Kids Definition of reactor

: a device using atomic energy to produce heat


re·​ac·​tor | \ rē-ˈak-tər How to pronounce reactor (audio) \

Medical Definition of reactor

1 : one that reacts: as
a : a chemical reagent
b : an individual reacting to a stimulus
c : an individual reacting positively to a foreign substance (as in a test for disease) reactors to tuberculin
2a : a piece of equipment in which a chemical reaction and especially an industrial chemical reaction is carried out
b : a device for the controlled release of nuclear energy (as for producing heat)

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More from Merriam-Webster on reactor

Rhyming Dictionary: Words that rhyme with reactor

Spanish Central: Translation of reactor

Nglish: Translation of reactor for Spanish Speakers

Britannica English: Translation of reactor for Arabic Speakers Encyclopedia article about reactor

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