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
Examples of plutonium in a Sentence
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Each spacecraft’s plutonium core produces a little less juice each year, however—annually losing about four watts, equivalent to a low-power light bulb.
—
Meghan Bartels, Scientific American, 6 Mar. 2025
In the months after Chang’s departure, the US sent specialists to dismantle a plutonium separation plant – a facility designed to extract nuclear materials for weapons production.
—Eric Cheung, CNN, 1 Mar. 2025
His first news conference was outside the Oppenheimer home, after a tour of the Los Alamos lab where he was introduced to plutonium pits, the key to many advanced nuclear weapons.
—Ian Dexter Palmer, Forbes, 28 Feb. 2025
The Massachusetts Legislature has been dodging an audit like it was made of plutonium.
—Boston Herald Editorial Staff, Boston Herald, 27 Feb. 2025
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Meghan Bartels, Scientific American, 6 Mar. 2025
In the months after Chang’s departure, the US sent specialists to dismantle a plutonium separation plant – a facility designed to extract nuclear materials for weapons production.
—Eric Cheung, CNN, 1 Mar. 2025
His first news conference was outside the Oppenheimer home, after a tour of the Los Alamos lab where he was introduced to plutonium pits, the key to many advanced nuclear weapons.
—Ian Dexter Palmer, Forbes, 28 Feb. 2025
The Massachusetts Legislature has been dodging an audit like it was made of plutonium.
—Boston Herald Editorial Staff, Boston Herald, 27 Feb. 2025
See All Example Sentences for plutonium
Cite this Entry
“Plutonium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/plutonium. Accessed 12 Mar. 2025.
Copy CitationKids Definition
plutonium
noun
plu·to·ni·um
plü-ˈtō-nē-əm
: a radioactive metallic element that is formed by decay of neptunium and found in minute quantities in pitchblende and that produces atomic energy by fission see element
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
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