Thorium
/ˈθɔːɹiəm/ noun
noun ·Rare ·Advanced level
Definitions
Noun
- 1 A chemical element (symbol Th) with atomic number 90. A weakly radioactive, malleable, moderately hard silvery metal that tarnishes black when exposed to air. uncountable, usually
- 2 a soft silvery-white tetravalent radioactive metallic element; isotope 232 is used as a power source in nuclear reactors; occurs in thorite and in monazite sands wordnet
Example
More examples"In examining a large number of minerals for helium, Strutt found that some samples of beryl, a beryllium aluminium silicate, contain a relatively very large amount of helium, but only traces of thorium, and were altogether inactive."
Etymology
From Thor + -ium.