urban center vs Busan

urban center and Busan both are nouns.

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

urban center (noun)	Busan (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in southeastern South Korea on the Korean Strait; the chief port and second largest city