square meter vs American spelling

square meter and American spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
square meter	Yes	No	No	No
American spelling	Yes	No	No	No

square meter (noun)	American spelling (noun)
a unit of measurement for area, defined as the area of a square with sides of exactly 1 metre; a centiare is 1/100th of an are	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')