lanthanide lanthana • lanthanite · · · Info · Definitions · Synonyms · Characters · · lanthanide · · Text Latin · · Script 10 · · Length Definitions · · · (noun) any element of the lanthanide series (atomic numbers 57 through 71). Synonyms: rare earth, rare-earth element, lanthanoid, lanthanon. · · Noun Definition 1 Synonyms · · · rare earth · · Synonym 1 rare-earth element · · Synonym 2 lanthanoid · · Synonym 3 lanthanon · · Synonym 4 Characters · · a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E t latin small letter t U+0074