metropolis vs Milan

metropolis and Milan both are nouns.

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

metropolis (noun)	Milan (noun)
people living in a large densely populated municipality	the capital of Lombardy in northern Italy; has been an international center of trade and industry since the Middle Ages
a large and densely populated urban area; may include several independent administrative districts