urban center vs Luluabourg

urban center and Luluabourg both are nouns.

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

urban center (noun)	Luluabourg (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in southwestern Congo; former name (until 1966) was Luluabourg