Timbuktu vs urban center

Timbuktu and urban center both are nouns.

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

Timbuktu (noun)	urban center (noun)
a city in central Mali near the Niger river; formerly famous for its gold trade	a large and densely populated urban area; may include several independent administrative districts