Lu vs atomic number 71

Lu and atomic number 71 both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lu	Yes	No	No	No
atomic number 71	Yes	No	No	No

As nouns, Lu and atomic number 71 are synonyms defined as:

Lu and atomic number 71: a trivalent metallic element of the rare earth group; usually occurs in association with yttrium

Other synonyms of Lu include lutecium, lutetium.

Lu (noun)	atomic number 71 (noun)
a trivalent metallic element of the rare earth group; usually occurs in association with yttrium	a trivalent metallic element of the rare earth group; usually occurs in association with yttrium