urban center vs Maracaibo

urban center and Maracaibo both are nouns.

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

urban center (noun)	Maracaibo (noun)
a large and densely populated urban area; may include several independent administrative districts	a port city in northwestern Venezuela; a major oil center