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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In water utilities in Texas and Colorado, levels of radium were found well above even double the EPA's limit.
—
Jasmine Laws, MSNBC Newsweek, 11 July 2025
The Times found that 128 wells generated waste water with levels of gross alpha--radiation from radium, uranium, and other radioactive materials--that exceeded Federal drinking water standards, in some cases by a factor of 2,700.
—IEEE Spectrum, 1 Mar. 2011
Radioactivity is a natural process where some atoms – like uranium, thorium and radium – break down on their own, releasing energy.
—André O. Hudson, The Conversation, 26 June 2025
Brine can contain elevated levels of heavy metals like lead and arsenic, and often so much radium that, under certain Environmental Protection Agency guidelines, it would be classified as radioactive waste.
—Justin Nobel, Harper's Magazine, 2 Jan. 2025
See All Example Sentences for radium
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Jasmine Laws, MSNBC Newsweek, 11 July 2025
The Times found that 128 wells generated waste water with levels of gross alpha--radiation from radium, uranium, and other radioactive materials--that exceeded Federal drinking water standards, in some cases by a factor of 2,700.
—IEEE Spectrum, 1 Mar. 2011
Radioactivity is a natural process where some atoms – like uranium, thorium and radium – break down on their own, releasing energy.
—André O. Hudson, The Conversation, 26 June 2025
Brine can contain elevated levels of heavy metals like lead and arsenic, and often so much radium that, under certain Environmental Protection Agency guidelines, it would be classified as radioactive waste.
—Justin Nobel, Harper's Magazine, 2 Jan. 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 6 Aug. 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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