/ ˈreɪdɒn; NAmE -dɑːn/ noun
[ U ] ( symb Rn ) a chemical element that is a radioactive gas used in the treatment of diseases such as cancer.
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WORD ORIGIN
early 20th cent.: from radium , on the pattern of argon .
/ ˈreɪdɒn; NAmE -dɑːn/ noun
[ U ] ( symb Rn ) a chemical element that is a radioactive gas used in the treatment of diseases such as cancer.
••
WORD ORIGIN
early 20th cent.: from radium , on the pattern of argon .
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005