American spelling vs amphitheater

American spelling and amphitheater both are nouns.

Word	Noun	Adjective	Verb	Adverb
American spelling	Yes	No	No	No
amphitheater	Yes	No	No	No

American spelling (noun)	amphitheater (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	an oval large stadium with tiers of seats; an arena in which contests and spectacles are held
	a sloping gallery with seats for spectators (as in an operating room or theater)