plutonium
noun
plu·to·ni·um plü-ˈtō-nē-əm 
: 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
Example Sentences
Recent Examples on the Web Second is regulation: Many states make dealing with weed more complex than handling weapons-grade plutonium. 
Will Yakowicz, Forbes, 2 Aug. 2022 Wildfires that reach the Los Alamos National Laboratory increase the risk, however slightly, of disbursing chemical waste and radionuclides such as plutonium through the air or in the ashes carried away by runoff after a fire. Morgan Lee, The Christian Science Monitor, 16 May 2022 Wildfires that reach the Los Alamos National Laboratory increase the risk, however slightly, of disbursing chemical waste and radionuclides such as plutonium through the air or in the ashes carried away by runoff after a fire. Morgan Lee, BostonGlobe.com, 14 May 2022 Jay Coghlan, director of the environmental group Nuclear Watch New Mexico, wants a more thorough evaluation of the lab's current fire risks and questions whether plutonium pit production is appropriate. Morgan Lee, The Christian Science Monitor, 16 May 2022 Most notably, in an issue of their first Marvel comic book run, the Joes prevent Cobra from putting plutonium in the Alaska Pipeline. David Reamer, Anchorage Daily News, 2 May 2022 But, beyond plutonium and uranium, what other radioisotopes are at play here? Hart Rapaport, Scientific American, 4 Apr. 2022 In Richland, Washington, the US government financed a fleet of nuclear reactors to manufacture plutonium. Jeremi Suri And Clark Miller, CNN, 24 Mar. 2022 The center of the site was used to produce plutonium from World War II through the Cold War. Tribune News Service, oregonlive, 1 Mar. 2022 See More
Will Yakowicz, Forbes, 2 Aug. 2022 Wildfires that reach the Los Alamos National Laboratory increase the risk, however slightly, of disbursing chemical waste and radionuclides such as plutonium through the air or in the ashes carried away by runoff after a fire. Morgan Lee, The Christian Science Monitor, 16 May 2022 Wildfires that reach the Los Alamos National Laboratory increase the risk, however slightly, of disbursing chemical waste and radionuclides such as plutonium through the air or in the ashes carried away by runoff after a fire. Morgan Lee, BostonGlobe.com, 14 May 2022 Jay Coghlan, director of the environmental group Nuclear Watch New Mexico, wants a more thorough evaluation of the lab's current fire risks and questions whether plutonium pit production is appropriate. Morgan Lee, The Christian Science Monitor, 16 May 2022 Most notably, in an issue of their first Marvel comic book run, the Joes prevent Cobra from putting plutonium in the Alaska Pipeline. David Reamer, Anchorage Daily News, 2 May 2022 But, beyond plutonium and uranium, what other radioisotopes are at play here? Hart Rapaport, Scientific American, 4 Apr. 2022 In Richland, Washington, the US government financed a fleet of nuclear reactors to manufacture plutonium. Jeremi Suri And Clark Miller, CNN, 24 Mar. 2022 The center of the site was used to produce plutonium from World War II through the Cold War. Tribune News Service, oregonlive, 1 Mar. 2022 See More Word History
Etymology
New Latin, from Pluton-, Pluto, the planet Pluto
First Known Use
1942, in the meaning defined above
Kids Definition
plutonium
noun
plu·to·ni·um plü-ˈtō-nē-əm
: a radioactive metallic chemical element formed from neptunium and used for releasing atomic energy
Medical Definition
plutonium
noun
plu·to·ni·um plü-ˈtō-nē-əm
: 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