rare earth

Definition

Any of the naturally occurring oxides of the lanthanide metals; they are widely distributed in relatively small concentrations and are used in glassmaking, ceramic glazes etc.

Etymology

From rare + earth. First use appears c. 1841 in the publications of Henry Minchin Noad. See cite below.

Example Sentences

• "Meronyms: rare earth element, rare earth metal"
• "The metallic base of yttria, a very rare earth, discovered in a mineral called godolinite."
• "Near-synonym: lanthanide"