American spelling vs call center

American spelling and call center both are nouns.

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

American spelling (noun)	call center (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	a center equipped to handle a large volume of telephone calls (especially for taking orders or serving customers)