proterozoic vs geology

proterozoic is not a noun while geology is a noun.

Word	Noun	Adjective	Verb	Adverb
proterozoic	No	Yes	No	No
geology	Yes	No	No	No

proterozoic (noun)	geology (noun)
	a science that deals with the history of the earth as recorded in rocks

proterozoic (adjective)	geology (adjective)
formed in the later of two divisions of the Precambrian era