urban center vs Aden

urban center and Aden both are nouns.

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

urban center (noun)	Aden (noun)
a large and densely populated urban area; may include several independent administrative districts	an important port of Yemen; located on the Gulf of Aden; its strategic location has made it a major trading center of southern Arabia since ancient times