city vs Columbus

city and Columbus both are nouns.

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

city (noun)	Columbus (noun)
people living in a large densely populated municipality	the state capital of Ohio; located in the center of the state; site of Ohio State University
a large and densely populated urban area; may include several independent administrative districts	a city in western Georgia on the Chattahoochee River; industrial center
an incorporated administrative district established by state charter	a town in eastern Mississippi near the border with Alabama
	Italian navigator who discovered the New World in the service of Spain while looking for a route to China (1451-1506)