ra·​don | \ ˈrā-ˌdän How to pronounce radon (audio) \

Definition of radon

: a heavy radioactive gaseous element formed by the decay of radium — see Chemical Elements Table

Examples of radon in a Sentence

Recent Examples on the Web

Like all rocks, granite does emit radiation in the form of trace amounts of radon gas. Hannah Morrill, ELLE Decor, "The Main Differences Between Quartz and Granite," 17 June 2019 The Middletown health department is offering free radon test kits for local homeowners. Shawn R. Beals, Courant Community, "Middletown Health Department Offering Free Radon Test Kits," 7 Mar. 2018 Naturally infused with low levels of radon, these healing springs continue to attract visitors who want to boost their immune systems or manage inflammatory illnesses. Elizabeth Wellington, Vogue, "This Austrian Spa and Ski Town Is Straight Out of a Wes Anderson Film," 11 Jan. 2019 Most filters on the market are designed to capture particles like dust and pollen, but don’t catch gases like VOCs (volatile organic compounds) or radon. Rachel Rothman, Good Housekeeping, "Do Air Purifiers Actually Work?," 17 Dec. 2018 One out of every 15 houses in suburban America is thought to have unacceptably high radon levels. Houston Chronicle, "YouDocs0514," 13 May 2018 The school board approved spending up to $50,000 on radon testing at a meeting Monday, but Tijerina said the projected testing cost would be around $35,600. Sarah Freishtat, Aurora Beacon-News, "East Aurora to test buildings for radon," 17 Apr. 2018 The remaining 15 percent of the funds raised would be used to assist homeowners whose homes are sinking in New Haven and others dealing with lead and radon abatement. Sandra Gomez-aceves, courant.com, "Capitol Roundup: Crumbling Foundations, Hartford Bailout Revision Bills Get Final Approval," 10 May 2018 But unlike cosmic radiation or radon gas, plutonium can lodge itself inside the body and deliver tissue-damaging alpha particles over a lifetime. Ted Sickinger, OregonLive.com, "Police looking for shooter after one injured in Keizer," 22 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of radon

1918, in the meaning defined above

History and Etymology for radon

International Scientific Vocabulary, from radium

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Dictionary Entries near radon





radon seed



Statistics for radon

Last Updated

3 Jul 2019

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Time Traveler for radon

The first known use of radon was in 1918

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English Language Learners Definition of radon

: a radioactive element which is a gas that is used medically in cancer treatments


ra·​don | \ ˈrā-dän How to pronounce radon (audio) \

Medical Definition of radon

: a heavy radioactive gaseous element of the group of inert gases formed by disintegration of radium and used similarly to radium in medicine symbol Rn

called also radium emanation

— see Chemical Elements Table

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More from Merriam-Webster on radon

Rhyming Dictionary: Words that rhyme with radon

Spanish Central: Translation of radon

Nglish: Translation of radon for Spanish Speakers

Britannica English: Translation of radon for Arabic Speakers

Britannica.com: Encyclopedia article about radon

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