radon

noun

ra·​don ˈrā-ˌdän 

: 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

Order a low-cost radon test kit from the American Lung Association. —Ryan Brennan, Kansas City Star, 19 May 2026

Low-cost radon test kits are available through the American Lung Association or by calling 1-800-SOS-RADON. —Ryan Brennan may 19, Charlotte Observer, 19 May 2026

That means family history, radon exposure, occupational risk, military exposure. —Armstrong Williams, Baltimore Sun, 1 May 2026

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

Word History

Etymology

International Scientific Vocabulary, from radium

First Known Use

1918, in the meaning defined above

Rhymes for radon

• anton
• argon
• axon
• baronne
• baryon
• baton
• boron
• buisson
• bygone
• capon
• cardon
• chiffon

Kids Definition

radon

noun

ra·​don ˈrā-ˌdän 

: a heavy radioactive gaseous element formed by the breaking apart of radium atoms see element

Medical Definition

radon

noun

ra·​don ˈrā-dän 

: 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