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English definition of “radon”


noun [U]     /ˈreɪ.dɒn/ US  /-dɑːn/ (symbol Rn)
a chemical element that is a radioactive gas formed when radium decays and found naturally in rock and soil: Tests showed high radon levels.Chemical elements
(Definition of radon noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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