Knoxville vs urban center

Knoxville and urban center both are nouns.

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

Knoxville (noun)	urban center (noun)
a city in eastern Tennessee on the Tennessee River	a large and densely populated urban area; may include several independent administrative districts