urban center vs Madras

urban center and Madras both are nouns.

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

urban center (noun)	Madras (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in Tamil Nadu on the Bay of Bengal; formerly Madras
	a state in southeastern India on the Bay of Bengal (south of Andhra Pradesh); formerly Madras