American spelling vs keratinize

American spelling is a noun but keratinize is not a noun.

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

American spelling (noun)	keratinize (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')

American spelling (verb)	keratinize (verb)
	become horny and impregnated with keratin
	convert into keratin