What does "thorium" mean?

A chemical element (symbol Th) with atomic number 90. A weakly radioactive, malleable, moderately hard silvery metal that tarnishes black when exposed to air.

What is a synonym for "thorium"?

Common synonyms include: atomic number 90, th, thorinum, thorinum.

Thorium

//ˈθɔːɹiəm// noun

noun ·Uncommon ·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

Synonyms

All synonyms

atomic number 90 th thorinum thorinum

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.

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.