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

Atomos, as its name alludes, plans to power its ever-circling vehicle with a nuclear reactor, starting in the mid-2020s. Sarah Scoles, WIRED, "Here Come the Space Tugs, Ready to Tidy Up Earth's Orbits," 22 Aug. 2019 Once a seed is created, the company puts it in a growth reactor, where it’s fed a very pure form of natural gas that contains only carbon atoms. Emily Price, Fortune, "Curious What Jony Ive Might Design After Apple? This Ring Might Be a Clue," 17 Aug. 2019 Spent fuel, when initially taken from a nuclear reactor, is dangerously radioactive. Wired, "A Strange Radioactive Cloud Likely Came From Russia," 15 Aug. 2019 Authorities took days to admit what happened, first spreading disinformation to the public before conceding that there was some kind of malfunction with a nuclear reactor. Alex Ward, Vox, "What caused Russia’s radioactive explosion last week? Possibly a nuclear-powered missile.," 13 Aug. 2019 Tucked away in the forests near the reactor is the Duga-3 radar station. Dallas News, "Decades after nuclear disaster, tourism is booming at Chernobyl," 18 June 2019 The reactor is basically a huge block of graphite in which uranium pellets were inserted, instigating a nuclear chain reaction that produced plutonium. William M. Gurstelle, Twin Cities, "Good ol’ Rocky Top: Visit the history, music, science of northeast Tennessee," 15 June 2019 Saudi officials have suggested the nuclear reactors would be useful in pursuing sea-water desalination, but the secretive nature of the acquisitions has led to concerns of a wider agenda. Nick Paton Walsh, CNN, "Saudi Arabia and the arms race that you've not heard enough about," 8 June 2019 The paperwork appeared to indicate that the Syrian reactor was much closer to completion than previously reported. Fox News, "Israel admits bombing Syrian nuclear site in 2007, says it's warning to Iran," 21 Mar. 2018

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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Last Updated

27 Aug 2019

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Time Traveler for reactor

The first known use of reactor was in 1890

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More Definitions for reactor



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

Comments on reactor

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


to make a temporary encampment

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