metropolis vs medical center

metropolis and medical center both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
medical center	Yes	No	No	No

metropolis (noun)	medical center (noun)
people living in a large densely populated municipality	the part of a city where medical facilities are centered
a large and densely populated urban area; may include several independent administrative districts