American spelling vs cubic kilometer

American spelling and cubic kilometer both are nouns.

Word	Noun	Adjective	Verb	Adverb
American spelling	Yes	No	No	No
cubic kilometer	Yes	No	No	No

American spelling (noun)	cubic kilometer (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	a unit of capacity equal to the volume of a cube one kilometer on each edge