metropolis vs Cotonou

metropolis and Cotonou both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Cotonou	Yes	No	No	No

metropolis (noun)	Cotonou (noun)
people living in a large densely populated municipality	chief port of Benin on the Bight of Benin
a large and densely populated urban area; may include several independent administrative districts