American spelling vs immobilization

American spelling and immobilization both are nouns.

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

American spelling (noun)	immobilization (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	the act of limiting movement or making incapable of movement
	fixation (as by a plaster cast) of a body part in order to promote proper healing