civic center vs metropolis

civic center and metropolis both are nouns.

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

civic center (noun)	metropolis (noun)
a center where the members of a community can gather for social or cultural activities	people living in a large densely populated municipality
the center of a city	a large and densely populated urban area; may include several independent administrative districts