urban center vs Herculaneum

urban center and Herculaneum both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
Herculaneum	Yes	No	No	No

urban center (noun)	Herculaneum (noun)
a large and densely populated urban area; may include several independent administrative districts	ancient city; now destroyed