cerium

• cererium (a name proposed (but not accepted) to indicate "cerium" does not come from the Greek word for "wax")

From Ceres (“a recently discovered asteroid”) +‎ -ium.

• enPR: sîr'ēəm, IPA^(key): /ˈsɪəɹiəm/

• Audio (Southern England):

  (file)

• Audio (General American):

  (file)

• Rhymes: -ɪəɹiəm

cerium (usually uncountable, plural ceriums)

2. A chemical element (symbol Ce) with an atomic number of 58, a very soft, ductile, silvery-white metal that tarnishes when exposed to air.
   • 2025 July 18, Timothy McLaughlin, “A Rebel Army Is Building a Rare-Earth Empire on China's Border. The Kachin Independence Organization fought for decades in obscurity. Now it's supplying essential minerals to manufacturers around the world”, in Bloomberg Businessweek‎^[1], archived from the original on 18 July 2025:

     Despite their name, rare earths are not so rare. The most common, cerium, is as plentiful in the Earth's crust as copper or lead. The difference between them and more familiar materials is that, in nature, rare earths are almost never found on their own. Rather, they're mixed with other minerals, and often at low concentrations, making them difficult to mine economically.

• Ceres
• ceria

• allanite
• bastnasite
• CAN
• hydroxylbastnasite
• jeweler's rouge, jeweller's rouge
• monazite
• orthite
• rhabdophane
• synchysite

• uremic

From Latin Ceres +‎ -ium.

cerium n (singular definite ceriummet, not used in plural form)

1. cerium

• “cerium” in Den Danske Ordbog

Borrowed from Swedish cerium, New Latin cerium or French cérium.

• IPA^(key): /ˈseː.riˌʏm/

• Audio:

  (file)

• Hyphenation: ce‧ri‧um

cerium n (uncountable, no diminutive)

1. cerium [from 1830s or earlier]

Internationalism (see English cerium).

• IPA^(key): /ˈseːri.um/, [ˈs̠e̞ːri.um]
• Rhymes: -eːri.um

cerium

1. cerium

From Ancient Greek κηρίον (kēríon).

• (Classical Latin) IPA^(key): [ˈkeː.ri.ũː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈt͡ʃɛː.ri.um]

cērium n (genitive cēriī or cērī); second declension

1. A bad species of swelling or ulcer

Second-declension noun (neuter).

¹Found in older Latin (until the Augustan Age).

• (Classical Latin) IPA^(key): [ˈkɛ.ri.ũː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈt͡ʃɛː.ri.um]

cerium n (genitive ceriī); second declension

1. (New Latin) cerium

Second-declension noun (neuter).

• “cerium”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “cerium”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.

cerium n

1. cerium

• cerium in Svensk ordbok (SO)
• cerium in Svenska Akademiens ordlista (SAOL)
• cerium in Svenska Akademiens ordbok (SAOB)
• Svensk MeSH