metropolis vs Aarhus

metropolis and Aarhus both are nouns.

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

metropolis (noun)	Aarhus (noun)
people living in a large densely populated municipality	port city of Denmark in eastern Jutland
a large and densely populated urban area; may include several independent administrative districts