metropolis vs Jersey City

metropolis and Jersey City both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Jersey City	Yes	No	No	No

metropolis (noun)	Jersey City (noun)
people living in a large densely populated municipality	a city in northeastern New Jersey (opposite Manhattan)
a large and densely populated urban area; may include several independent administrative districts