city center vs American spelling

city center and American spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
city center	Yes	No	No	No
American spelling	Yes	No	No	No

city center (noun)	American spelling (noun)
the central part of a city	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')