often attributive
: an intensely radioactive metallic chemical element that occurs in combination in minute quantities in minerals (such as pitchblende or carnotite), emits alpha particles and gamma rays to form radon, and is used chiefly in the treatment of cancer and in radiographic devices see Chemical Elements Table
Examples of radium in a Sentence
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Effects on the human body The nuclear radiation emitted when radium and other elements decay can damage the cells in the human body.
—
Kelling Donald, The Conversation, 13 Oct. 2025
When Marie Curie’s new glowing discovery first hit the market, jewelers embedded radium in pendants and bracelets and sold them as chic wellness accessories—until decades later, people started dying of cancer.
—Eva Roytburg, Fortune, 1 Oct. 2025
Burnham Yard also is near an Environmental Protection Agency Superfund site for radium contamination, but the Terracon report did not find any indication that there is a substantial amount of radioactive material underground.
—Elliott Wenzler, Denver Post, 14 Sep. 2025
The colony is endowed with rubber and radium, copper and palm oil.
—Big Think, 26 Aug. 2025
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Kelling Donald, The Conversation, 13 Oct. 2025
When Marie Curie’s new glowing discovery first hit the market, jewelers embedded radium in pendants and bracelets and sold them as chic wellness accessories—until decades later, people started dying of cancer.
—Eva Roytburg, Fortune, 1 Oct. 2025
Burnham Yard also is near an Environmental Protection Agency Superfund site for radium contamination, but the Terracon report did not find any indication that there is a substantial amount of radioactive material underground.
—Elliott Wenzler, Denver Post, 14 Sep. 2025
The colony is endowed with rubber and radium, copper and palm oil.
—Big Think, 26 Aug. 2025
See All Example Sentences for radium
Cite this Entry
“Radium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radium. Accessed 31 Oct. 2025.
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Medical Definition
radium
noun
ra·di·um
ˈrād-ē-əm 
often attributive
: an intensely radioactive shining white metallic element that resembles barium chemically, that occurs in combination in minute quantities in minerals (as pitchblende or carnotite) principally as the isotope of mass number 226 formed from uranium 238, having a half-life of 1620 years, and emitting alpha particles and gamma rays to form radon, and that is used chiefly in luminous materials and in the treatment of cancer
—symbol Ra
see Chemical Elements Table
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