US English orthography vs American spelling

US English orthography and American spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
US English orthography	Yes	No	No	No
American spelling	Yes	No	No	No

As nouns, US English orthography and American spelling are synonyms defined as:

US English orthography and American spelling: English orthography used in the United States (characterized by 'analyze', 'center', 'usable')

Other synonyms of US English orthography include American English orthography, American English spelling, US English spelling, US spelling.

US English orthography (noun)	American spelling (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')