Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun plutonium

1 sense of plutonium

Sense 1
plutonium, Pu, atomic number 94 -- (a solid silvery grey 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)
       => chemical element, element -- (any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter)