metropolis vs Pergamum

metropolis and Pergamum both are nouns.

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

metropolis (noun)	Pergamum (noun)
people living in a large densely populated municipality	an ancient Greek city located in the western part of what is now modern Turkey; the technique of preparing sheepskins as parchment was developed here
a large and densely populated urban area; may include several independent administrative districts