endeavor vs American spelling

endeavor and American spelling both are nouns.

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

endeavor (noun)	American spelling (noun)
earnest and conscientious activity intended to do or accomplish something	English orthography used in the United States (characterized by 'analyze', 'center', 'usable')
a purposeful or industrious undertaking (especially one that requires effort or boldness)

endeavor (verb)	American spelling (verb)
attempt by employing effort