A group of fifteen closely related elements, not so rare as once thought. They are also called lanthanides for lanthanum, the lead member of the group. Mixtures of rare earth ions are used as components in FCC catalysts.

Any of a group of 15 similar metals with atomic numbers 57 to 71. Also rare earth element, rare earth metal, lanthanide series, uncommon metals, Mischmetal.

Rare Earth was an American rock band affiliated with Motown's Rare Earth record label (which was named after the band) in the late-1960s and 1970s. Although not the first White band signed to Motown, Rare Earth were the first big hit-making act signed by Motown that consisted entirely of White American members.