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
Recent Examples on the Web
Both radium and radon are radioactive and can cause cancer.
—
Shawn Tully, Fortune, 9 Oct. 2024
The hands and indexes are delicately filled with egg-shell colored Super-LumiNova, reflecting the radium originally used, ensuring visibility in all lighting conditions.
—Bhanu Chopra, Forbes, 3 Sep. 2024
It’s inferred that this strange symbol is indicative of a radium dial that conforms to Atomic Energy Commission guidelines from 1960, and that uses less radioactive material than earlier 1950s-era timepieces.
—Oren Hartov, Robb Report, 4 July 2024
This byproduct of burning coal to generate power is full of heavy metals and toxic elements such as arsenic, mercury, chromium and even radium.
—Sarah Bowman, The Indianapolis Star, 20 Feb. 2024
See all Example Sentences for radium 
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Shawn Tully, Fortune, 9 Oct. 2024
The hands and indexes are delicately filled with egg-shell colored Super-LumiNova, reflecting the radium originally used, ensuring visibility in all lighting conditions.
—Bhanu Chopra, Forbes, 3 Sep. 2024
It’s inferred that this strange symbol is indicative of a radium dial that conforms to Atomic Energy Commission guidelines from 1960, and that uses less radioactive material than earlier 1950s-era timepieces.
—Oren Hartov, Robb Report, 4 July 2024
This byproduct of burning coal to generate power is full of heavy metals and toxic elements such as arsenic, mercury, chromium and even radium.
—Sarah Bowman, The Indianapolis Star, 20 Feb. 2024
See all Example Sentences for radium
Dictionary Entries Near radium
Cite this Entry
“Radium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radium. Accessed 14 Nov. 2024.
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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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