: a metallic chemical element that is the most abundant of the rare-earth group and is a chief component of misch metal see Chemical Elements Table
Examples of cerium in a Sentence
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The preserved melt formed deep within Earth and shows low levels of trace elements like niobium, uranium and cerium.
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David Bressan, Forbes.com, 31 Aug. 2025
Lynas Rare Earths explores and mines for rare earth minerals such as cerium and neodymium.
—Sam Meredith,dylan Butts, CNBC, 20 June 2025
Back then, of course, uses were limited: apart from europium adding vibrancy to L.A. cop procedurals, cerium was used as a glass polishing agent, while lanthanum was—and still is—crucial for oil cracking, or turning crude into gasoline and other lighter fuels.
—Charlie Campbell, Time, 17 June 2025
Why China dominates rare earths Rare earths are a group of 17 elements in the middle of the periodic table, including neodymium, cerium and scandium.
—Mithil Aggarwal, NBC news, 10 June 2025
Gadolinium is vital for MRI machines, while samarium and cerium play key roles in nuclear reactors and energy systems such as solar and wind power.
—Scott McWhorter, The Conversation, 6 May 2025
Rare-earth compounds take on a variety of colors, as shown with these oxides of (clockwise from top center): praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.
—IEEE Spectrum, 7 Mar. 2025
Lanthanum and cerium are among the most common rare earth metals.
—Jason Neely and Eric Onstad, USA TODAY, 27 Feb. 2025
Rare earth materials found in Ukraine include lanthanum and cerium, which are used in TVs and lighting; neodymium, which is used in wind energy and batteries; and erbium and yttrium, which are used in lasers, Reuters reported.
—Laura Kelly, The Hill, 16 Feb. 2025
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David Bressan, Forbes.com, 31 Aug. 2025
Lynas Rare Earths explores and mines for rare earth minerals such as cerium and neodymium.
—Sam Meredith,dylan Butts, CNBC, 20 June 2025
Back then, of course, uses were limited: apart from europium adding vibrancy to L.A. cop procedurals, cerium was used as a glass polishing agent, while lanthanum was—and still is—crucial for oil cracking, or turning crude into gasoline and other lighter fuels.
—Charlie Campbell, Time, 17 June 2025
Why China dominates rare earths Rare earths are a group of 17 elements in the middle of the periodic table, including neodymium, cerium and scandium.
—Mithil Aggarwal, NBC news, 10 June 2025
Gadolinium is vital for MRI machines, while samarium and cerium play key roles in nuclear reactors and energy systems such as solar and wind power.
—Scott McWhorter, The Conversation, 6 May 2025
Rare-earth compounds take on a variety of colors, as shown with these oxides of (clockwise from top center): praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.
—IEEE Spectrum, 7 Mar. 2025
Lanthanum and cerium are among the most common rare earth metals.
—Jason Neely and Eric Onstad, USA TODAY, 27 Feb. 2025
Rare earth materials found in Ukraine include lanthanum and cerium, which are used in TVs and lighting; neodymium, which is used in wind energy and batteries; and erbium and yttrium, which are used in lasers, Reuters reported.
—Laura Kelly, The Hill, 16 Feb. 2025
Cite this Entry
“Cerium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cerium. Accessed 31 Oct. 2025.
Copy CitationMedical Definition
cerium
noun
ce·ri·um
ˈsir-ē-əm 
: a malleable ductile metallic element that is the most abundant of the rare-earth group
—symbol Ce
see Chemical Elements Table
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