decolourize vs American spelling

decolourize is not a noun while American spelling is a noun.

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

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

decolourize (verb)	American spelling (verb)
cause to become white or lighter in color