urban center vs St. Louis

urban center and St. Louis both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
St. Louis	Yes	No	No	No

urban center (noun)	St. Louis (noun)
a large and densely populated urban area; may include several independent administrative districts	the largest city in Missouri; a busy river port on the Mississippi River near its confluence with the Missouri River; was an important staging area for wagon trains westward in the 19th century
	king of France and son of Louis VIII; he led two unsuccessful Crusades; considered an ideal medieval king (1214-1270)