Greenville vs urban center

Greenville and urban center both are nouns.

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

Greenville (noun)	urban center (noun)
a town in northwest South Carolina in the Piedmont	a large and densely populated urban area; may include several independent administrative districts
a town in western Mississippi on the Mississippi River to the north of Vicksburg
a city in eastern North Carolina; tobacco market