radiothorium

noun

ra·dio·tho·ri·um ˌrā-dē-ō-ˈthȯr-ē-əm

: a radioactive isotope of thorium with the mass number 228

Word History

Etymology

New Latin

First Known Use

1905, in the meaning defined above

Time Traveler

The first known use of radiothorium was in 1905

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radiothermics

radiothorium

radiotracer

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Cite this Entry

Style

“Radiothorium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radiothorium. Accessed 4 Nov. 2025.

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Medical Definition

radiothorium

noun

ra·dio·tho·ri·um -ˈthōr-ē-əm, -ˈthȯr-

: a radioactive isotope of thorium with the mass number 228

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