a gray chemical element, the most abundant of the rare-earth elements: it is used in alloys, electronic components, and nuclear fuels: symbol, Ce; at. no., 58
see the periodic table of elements in the Reference Supplement
See cerium in American Heritage Dictionary 4
(sîrˈē-əm)
noun Symbol Ce
A lustrous, iron-gray, malleable metallic rare-earth element that occurs chiefly in the minerals monazite and bastnaesite, exists in four allotropic states, is a constituent of lighter flint alloys, and is used in various metallurgical and nuclear applications. Atomic number 58; atomic weight 140.12; melting point 795°C; boiling point 3,468°C; specific gravity 6.67 to 8.23; valence 3, 4. See Table at element.