American spelling vs estrogen

American spelling and estrogen both are nouns.

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

American spelling (noun)	estrogen (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics