radon

noun

ra·​don ˈrā-ˌdän How to pronounce radon (audio)
: 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
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Nation-leading pesticide use, high nitrate and forever chemical levels in Iowa waters, and elevated radon exposure are among the environmental factors linked to the state's rising cancer rates, according to a new report from the Iowa Environment Council and Harkin Institute for Public Policy. Donnelle Eller, Des Moines Register, 26 Mar. 2026 Best air quality monitors This monitor detects radon, carbon dioxide, VOCs, humidity, temperature and atmospheric pressure, giving you a broad understanding of the quality of the air in your home. Bestreviews, Chicago Tribune, 17 Mar. 2026 This may involve sealing cracks in basement walls and foundations and installing a fan and vent pipe to pull radon gas from underneath the home and vent it outside. Jan Lowery, The Conversation, 20 Feb. 2026 Rehabilitating a house can take on many different forms, Pfeifer said, like replacing aging kitchen appliances, lead and asbestos abatement, radon mitigation or adding on a bedroom. Mars King, Twin Cities, 8 Feb. 2026 See All Example Sentences for radon

Word History

Etymology

International Scientific Vocabulary, from radium

First Known Use

1918, in the meaning defined above

Time Traveler
The first known use of radon was in 1918

Browse Nearby Words

Cite this Entry

“Radon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radon. Accessed 3 Apr. 2026.

Kids Definition

radon

noun
ra·​don ˈrā-ˌdän How to pronounce radon (audio)
: a heavy radioactive gaseous element formed by the breaking apart of radium atoms see element

Medical Definition

radon

noun
ra·​don ˈrā-dän How to pronounce radon (audio)
: 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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