urban center vs Knoxville

urban center and Knoxville both are nouns.

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

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