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 One out of every 15 homes is subject to radon exposure. Juno Demelo, Glamour, "6 Things Besides Cigarettes That Have Been Linked to Lung Cancer," 9 Oct. 2019 If there are direct pathways, the health effects are certain: The damage that arsenic, boron, chromium, and radon can do to humans is well-established in scientific literature. Emily Atkin, The New Republic, "Is Coal Waste Leaching Into America’s Drinking Water?," 12 Mar. 2018 Normal lung cells become cancerous through exposure to tobacco smoke, radon gas, asbestos or airborne pollutants. Richard Gunderman, The Conversation, "The test that could save the life of a long-time smoker you know," 2 Sep. 2019 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

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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Time Traveler for radon

Time Traveler

The first known use of radon was in 1918

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Statistics for radon

Last Updated

20 Nov 2019

Cite this Entry

“Radon.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/radon. Accessed 11 December 2019.

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More Definitions for radon


How to pronounce radon (audio)

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

Comments on radon

What made you want to look up radon? Please tell us where you read or heard it (including the quote, if possible).


heavy with or as if with moisture

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