American spelling vs US English orthography

American spelling and US English orthography both are nouns.

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

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

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

American spelling (noun)	US English orthography (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')