externalization vs American spelling

externalization and American spelling both are nouns.

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

externalization (noun)	American spelling (noun)
embodying in an outward form	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')
attributing to outside causes