Corpus Christi vs urban center

Corpus Christi and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
Corpus Christi	Yes	No	No	No
urban center	Yes	No	No	No

Corpus Christi (noun)	urban center (noun)
a city in southern Texas on an arm of the Gulf of Mexico	a large and densely populated urban area; may include several independent administrative districts
Thursday after Trinity Sunday; first celebrated in 1246