re·​ac·​tor | \rē-ˈak-tər \

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

Macron confirmed the first nuclear reactors to close will be those of Fessenheim, on the border with Germany, in a process that will start by 2020. Sylvie Corbet, The Seattle Times, "France’s Macron tries to ease popular anger over gas prices," 27 Nov. 2018 But within a few years, the reactor was back up and running. New York Times, "U.S. and North Korean Officials Race to Resurrect Trump-Kim Meeting," 27 May 2018 The talks later fell apart, and the reactor at Yongbyon is once again producing plutonium. Washington Post, "In North Korea nuke site closure, spectacle trumps substance," 23 May 2018 The four owners of the new additions to the Vogtle nuclear power plant in Georgia agreed on Thursday that construction on the two additional reactors can go forward. Megan Geuss, Ars Technica, "Vote results: Construction will continue on Vogtle nuclear power plant," 27 Sep. 2018 Plutonium can be acquired from reprocessing spent fuel from conventional nuclear power plants, or reactors can be designed specifically to produce plutonium for use in weapons. Umair Irfan, Vox, "Uranium enrichment will be a key point in talks with North Korea. Here’s what it is.," 11 June 2018 Its infrastructure – nuclear reactors and all – rivaled that of many much richer countries. Peter Schwartzstein, Smithsonian, "How Saddam and ISIS Killed Iraqi Science," 30 May 2018 The black mineral, when purified through a manufacturing process, is used in making nuclear reactors and missile components, in addition to other industrial applications. Author: Joby Warrick, Anchorage Daily News, "Suspicious factory underscores challenge of verifying North Korea’s nuclear promises," 22 Apr. 2018 In contrast, fast reactors split atoms with the raw high-energy neutrons. Adrian Cho, Science | AAAS, "Congress pushes for multibillion-dollar nuclear reactor that critics call a boondoggle," 3 July 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

3 Dec 2018

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The first known use of reactor was in 1890

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English Language Learners Definition of reactor

physics : a large device that produces nuclear energy


re·​ac·​tor | \rē-ˈak-tər \

Kids Definition of reactor

: a device using atomic energy to produce heat


re·​ac·​tor | \rē-ˈak-tər \

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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a soft lustrous wool fabric with mohair

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