Ann Arbor vs urban center

Ann Arbor and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ann Arbor	Yes	No	No	No
urban center	Yes	No	No	No

Ann Arbor (noun)	urban center (noun)
a city in southern Michigan near Detroit; site of the University of Michigan	a large and densely populated urban area; may include several independent administrative districts