city vs Aachen

city and Aachen both are nouns.

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

city (noun)	Aachen (noun)
people living in a large densely populated municipality	a city in western Germany near the Dutch and Belgian borders; formerly it was Charlemagne's northern capital
a large and densely populated urban area; may include several independent administrative districts
an incorporated administrative district established by state charter