staple fiber vs American spelling

staple fiber and American spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
staple fiber	Yes	No	No	No
American spelling	Yes	No	No	No

staple fiber (noun)	American spelling (noun)
a natural fiber (raw cotton, wool, hemp, flax) that can be twisted to form yarn	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')