nanometer vs American spelling

nanometer and American spelling both are nouns.

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

nanometer (noun)	American spelling (noun)
a metric unit of length equal to one billionth of a meter	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')