lanthanide vs rare earth

lanthanide and rare earth both are nouns.

Word	Noun	Adjective	Verb	Adverb
lanthanide	Yes	No	No	No
rare earth	Yes	No	No	No

As nouns, lanthanide and rare earth are synonyms defined as:

lanthanide and rare earth: any element of the lanthanide series (atomic numbers 57 through 71)

Other synonyms of lanthanide include lanthanoid, lanthanon, rare-earth element.

lanthanide (noun)	rare earth (noun)
any element of the lanthanide series (atomic numbers 57 through 71)	any element of the lanthanide series (atomic numbers 57 through 71)