Longman Dictionary of Contemporary English homepage

radioactive

 adjective
     
Related topics: Chemistry
ra‧di‧o‧ac‧tive
HC a radioactive substance is dangerous because it contains radiation (=a form of energy that can harm living things):
the problem of how to dispose of radioactive waste
a consignment of highly radioactive plutonium
Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.

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