From Thor +‎ -ium.

• enPR: thôr'ēəm, IPA^(key): /ˈθɔːɹiəm/

• Audio (US):

  (file)

• Rhymes: -ɔːɹiəm

thorium (usually uncountable, plural thoriums)

English Wikipedia has an article on:

thorium

Wikipedia

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

• thorinum (former alternative form; obsolete)

thorium

1. thorium

Dutch Wikipedia has an article on:

thorium

Wikipedia ^nl

Ultimately from Swedish torium or New Latin thorium. This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.

• IPA^(key): /ˈtoː.riˌʏm/

• Audio:

  (file)

• Hyphenation: tho‧ri‧um

thorium n (uncountable)

1. thorium [from mid 19th c.]

• thoriumcentrale
• thoriumreactor

French Wikipedia has an article on:

thorium

Wikipedia ^fr

• IPA^(key): /tɔ.ʁjɔm/

• Audio:

  (file)

thorium m (uncountable)

1. thorium

• “thorium”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

Latin Wikipedia has an article on:

thorium

Wikipedia ^la

• (Classical Latin) IPA^(key): /ˈtʰoː.ri.um/, [ˈt̪ʰoːriʊ̃ˑ]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈto.ri.um/, [ˈt̪ɔːrium]

thōrium n (genitive thōriī); second declension

1. (New Latin) thorium

Second-declension noun (neuter).

Norwegian Wikipedia has an article on:

thorium

Wikipedia ^no

From Thor, a variant of Tor, from Old Norse Þórr, +‎ -ium.

thorium n (definite singular thoriumet, uncountable)

1. thorium, chemical element, symbol Th

• “thorium” in The Bokmål Dictionary.
• “thorium” in Det Norske Akademis ordbok (NAOB).

Norwegian Nynorsk Wikipedia has an article on:

thorium

Wikipedia ⁿⁿ

From Thor, a variant of Tor, from Old Norse Þórr, +‎ -ium.

thorium n (definite singular thoriumet, uncountable)

1. thorium, chemical element, symbol Th

• “thorium” in The Nynorsk Dictionary.