/ Dictionary / Index R rare-earth element: Meaning and Definition of Find definitions for: rare'-earth' el"ement Pronunciation: (râr'ûrth'), [key] — Chem. Chem. any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rare earth raree show Related Content Daily Word Quiz: placate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language