urban center vs Omaha

urban center and Omaha both are nouns.

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

urban center (noun)	Omaha (noun)
a large and densely populated urban area; may include several independent administrative districts	thoroughbred that won the triple crown in 1935
	the Dhegiha dialect spoken by the Omaha
	largest city in Nebraska; located in eastern Nebraska on the Missouri river; a major transportation center of the Midwest
	a member of the Siouan people formerly living in the Missouri river valley in northeastern Nebraska