thorium
noun
tho·ri·um
ˈthȯr-ē-əm 
: a radioactive metallic element that is obtained especially from monazite and is usually associated with rare earths see Chemical Elements Table
Examples of thorium in a Sentence
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Few areas on the farside, with its dearth of volcanism, have a high abundance of thorium.
—
Keith Cooper, Space.com, 9 Apr. 2025
Australia, Brazil and the U.S. also boast large reserves of thorium, each possessing more than 500,000 tons.
—Russel Honoré, Newsweek, 6 Mar. 2025
While thorium holds promise as a potential cleaner, safer, and more sustainable form of nuclear energy, research and development into thorium reactors is still largely in the experimental phase.
—Russel Honoré, Newsweek, 6 Mar. 2025
Certain types of rare earth ores also contain radioactive thorium or uranium, which is often removed using acid.
—Jason Neely and Eric Onstad, USA TODAY, 27 Feb. 2025
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Keith Cooper, Space.com, 9 Apr. 2025
Australia, Brazil and the U.S. also boast large reserves of thorium, each possessing more than 500,000 tons.
—Russel Honoré, Newsweek, 6 Mar. 2025
While thorium holds promise as a potential cleaner, safer, and more sustainable form of nuclear energy, research and development into thorium reactors is still largely in the experimental phase.
—Russel Honoré, Newsweek, 6 Mar. 2025
Certain types of rare earth ores also contain radioactive thorium or uranium, which is often removed using acid.
—Jason Neely and Eric Onstad, USA TODAY, 27 Feb. 2025
See All Example Sentences for thorium
Cite this Entry
“Thorium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thorium. Accessed 23 Apr. 2025.
Copy CitationKids Definition
thorium
noun
tho·ri·um
ˈthōr-ē-əm
ˈthȯr-
: a radioactive metallic element see element
Medical Definition
thorium
noun
tho·ri·um
ˈthōr-ē-əm, ˈthȯr-
: a radioactive metallic element that occurs combined in minerals and is usually associated with rare earths
—symbol Th
see Chemical Elements Table
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