city vs Busan

city and Busan both are nouns.

Word	Noun	Adjective	Verb	Adverb
city	Yes	No	No	No
Busan	Yes	No	No	No

city (noun)	Busan (noun)
people living in a large densely populated municipality	a city in southeastern South Korea on the Korean Strait; the chief port and second largest city
a large and densely populated urban area; may include several independent administrative districts
an incorporated administrative district established by state charter