Definition of plutonium in English:

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Pronunciation: /plo͞oˈtōnēəm/


The chemical element of atomic number 94, a dense silvery radioactive metal of the actinide series, used as a fuel in nuclear reactors and as an explosive in nuclear fission weapons. Plutonium only occurs in trace amounts in nature but is manufactured in nuclear reactors from uranium-238. (Symbol: Pu)
Example sentences
  • The only manufacturing left on the site when reprocessing goes will be the plant for making nuclear fuel from plutonium and uranium oxides.
  • Workers at the facility were exposed to radiation as well as the chemicals uranium, plutonium and fluorine.
  • To develop a comprehensive set of nuclear weapons, enriched plutonium and uranium are needed.


1940s: from Greek Ploutōn 'Pluto', on the pattern of neptunium, being the next planet beyond Neptune.

Words that rhyme with plutonium

ammonium, euphonium, harmonium, pandemonium, pelargonium, polonium, zirconium

For editors and proofreaders

Syllabification: plu·to·ni·um

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