plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Definition of plutonium

: a radioactive metallic element similar chemically to uranium that is formed as the isotope 239 by decay of neptunium and found in minute quantities in pitchblende, that undergoes slow disintegration with the emission of an alpha particle to form uranium 235, and that is fissionable with slow neutrons to yield atomic energy — see Chemical Elements Table

Examples of plutonium in a Sentence

Recent Examples on the Web

Missing were radiation detectors and small samples of plutonium and cesium used to calibrate them. Dan Goodin, Ars Technica, "Dangerous plutonium stolen from rental car in a hotel parking lot," 16 July 2018 At least two buildings hold reactors, one credited with making the plutonium that fueled some of North Korea’s atom bombs. David E. Sanger And William J. Broad, New York Times, "Verifying the End of a Nuclear North Korea ‘Could Make Iran Look Easy’," 6 May 2018 That report cites a series of delays and cost overruns at the agency, including a contentious project to reprocess weapons-grade plutonium and uranium into fuel for commercial reactors at a site in South Carolina. Matthew Daly, The Seattle Times, "Congress drops bid to loosen supervision of nuclear agency," 24 July 2018 That report cites a series of delays and cost overruns at the agency, including a contentious project to reprocess weapons-grade plutonium and uranium into fuel for commercial reactors. Matthew Daly, Fox News, "Congress considers changing supervision of nuclear weapons," 23 July 2018 Radiation detectors and dime-sized disks of plutonium and cesium used to make sure the detectors were working properly. Rachel Becker, The Verge, "The US government has trouble keeping track of radioactive material," 17 July 2018 The experts from the Energy Department’s Idaho National Laboratory were sent to San Antonio to retrieve the plutonium and cesium on March 21, 2017, according to a Monday report from The Center for Public Integrity. Ryan Gaydos, Fox News, "Nuclear materials were reportedly stolen in Texas last year -- and they still haven't been found," 16 July 2018 Any amount of plutonium is also highly carcinogenic. Dan Goodin, Ars Technica, "Dangerous plutonium stolen from rental car in a hotel parking lot," 16 July 2018 And once the Agreed Framework collapsed, North Korea took the secured plutonium under its control and built about half a dozen additional nuclear weapons, testing its first in 2006. chicagotribune.com, "John Bolton is a national security threat," 23 Mar. 2018

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

1942, in the meaning defined above

History and Etymology for plutonium

New Latin, from Pluton-, Pluto, the planet Pluto

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Statistics for plutonium

Last Updated

10 Jun 2019

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Time Traveler for plutonium

The first known use of plutonium was in 1942

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More Definitions for plutonium

plutonium

noun

English Language Learners Definition of plutonium

: a radioactive element that is used to make nuclear energy and nuclear weapons

plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Kids Definition of plutonium

: a radioactive metallic chemical element formed from neptunium and used for releasing atomic energy

plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Medical Definition of plutonium

: a radioactive metallic element similar chemically to uranium that is formed as the isotope 239 by decay of neptunium and found in minute quantities in pitchblende, that undergoes slow disintegration with the emission of an alpha particle to form uranium 235, and that is fissionable with slow neutrons to yield atomic energy symbol Pu — see Chemical Elements Table

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More from Merriam-Webster on plutonium

Rhyming Dictionary: Words that rhyme with plutonium

Spanish Central: Translation of plutonium

Nglish: Translation of plutonium for Spanish Speakers

Britannica.com: Encyclopedia article about plutonium

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