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radiothorium

American  
[rey-dee-oh-thawr-ee-uhm, -thohr-] / ˌreɪ di oʊˈθɔr i əm, -ˈθoʊr- /

noun

Chemistry.
  1. a disintegration product of thorium.


Etymology

Origin of radiothorium

From New Latin, dating back to 1920–25; radio-, thorium