rare-earth element rare earth • rare-earth metal · · · Info · Definitions · Synonyms · Characters · · rare-earth element · · Text Common · · Latin · · Scripts 18 · · Length 6 · · Syllables Definitions · · · (noun) any element of the lanthanide series (atomic numbers 57 through 71). Synonyms: rare earth, rare-earth element, lanthanoid, lanthanide, lanthanon. · · Noun Definition 1 Synonyms · · · rare earth · · Synonym 1 lanthanoid · · Synonym 2 lanthanide · · Synonym 3 lanthanon · · Synonym 4 Characters · · space U+0020 - hyphen-minus U+002D a latin small letter a U+0061 e latin small letter e U+0065 h latin small letter h U+0068 l latin small letter l U+006C m latin small letter m U+006D n latin small letter n U+006E r latin small letter r U+0072 t latin small letter t U+0074