Rotterdam vs urban center

Rotterdam and urban center both are nouns.

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

Rotterdam (noun)	urban center (noun)
the 2nd largest city in the Netherlands; located in the western Netherlands near the North Sea	a large and densely populated urban area; may include several independent administrative districts