stimulus generalization vs American spelling

stimulus generalization and American spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
stimulus generalization	Yes	No	No	No
American spelling	Yes	No	No	No

stimulus generalization (noun)	American spelling (noun)
(psychology) transfer of a response learned to one stimulus to a similar stimulus	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')