dead center vs American spelling

dead center and American spelling both are nouns.

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

dead center (noun)	American spelling (noun)
the position of a crank when it is in line with the connecting rod and not exerting torque	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')