plutonium

Noun

1.

plutonium - a solid silvery gray radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239 Synonyms: atomic number 94, Pu

atomic number 94, chemical element, element, plutonium 239, Pu