Tb vs atomic number 65

Tb and atomic number 65 both are nouns.

Word	Noun	Adjective	Verb	Adverb
Tb	Yes	No	No	No
atomic number 65	Yes	No	No	No

As nouns, Tb and atomic number 65 are synonyms defined as:

Tb and atomic number 65: a metallic element of the rare earth group; used in lasers; occurs in apatite and monazite and xenotime and ytterbite

Other synonyms of Tb include terbium.

Tb (noun)	atomic number 65 (noun)
a unit of information equal to 1000 gigabits or 10^12 (1,000,000,000,000) bits	a metallic element of the rare earth group; used in lasers; occurs in apatite and monazite and xenotime and ytterbite
a metallic element of the rare earth group; used in lasers; occurs in apatite and monazite and xenotime and ytterbite