Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “plutonium”


noun [U]     /pluːˈtəʊ.ni.əm/ US  /-ˈtoʊ-/ (symbol Pu)
a chemical element that is a metal used in the production of nuclear power , and in nuclear weapons Chemical elements
(Definition of plutonium noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of plutonium

Definitions of “plutonium” in other dictionaries

Word of the Day


a good knowledge of something, or the fact that you know it so well

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More