urban center vs Brownsville

urban center and Brownsville both are nouns.

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

urban center (noun)	Brownsville (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in southern Texas on the Rio Grande near its mouth into the Gulf of Mexico; has a channel that accommodates oceangoing ships