city vs Knoxville

city and Knoxville both are nouns.

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

city (noun)	Knoxville (noun)
people living in a large densely populated municipality	a city in eastern Tennessee on the Tennessee River
a large and densely populated urban area; may include several independent administrative districts
an incorporated administrative district established by state charter