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

And who has the responsibility to get rid of the radon? —Jill Terreri Ramos, New York Times, 26 Apr. 2025

Even so, fixing radon on a large scale can seem like playing a carnival game of whack-a-mole as parts of Idaho continue to see dramatically high levels of the gas. —Nick Rosenberger, Idaho Statesman, 22 Apr. 2025

First, there is no building in the United States without some radon. —Nick Rosenberger, Idaho Statesman, 22 Apr. 2025

While that’s the most common environmental issue, alarm bells should sound if your inspector turns up asbestos or radon as well. —Berit Thorkelson, Better Homes & Gardens, 1 Apr. 2025

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