Atlantic City vs urban center

Atlantic City and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
Atlantic City	Yes	No	No	No
urban center	Yes	No	No	No

Atlantic City (noun)	urban center (noun)
a city on the Atlantic shore in southeastern New Jersey; a resort and gambling center	a large and densely populated urban area; may include several independent administrative districts