Aachen vs urban center

Aachen and urban center both are nouns.

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

Aachen (noun)	urban center (noun)
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