estriol vs oestrogen

estriol and oestrogen both are nouns.

Word	Noun	Adjective	Verb	Adverb
estriol	Yes	No	No	No
oestrogen	Yes	No	No	No

As nouns, oestrogen is a hypernym of estriol; that is, oestrogen is a word with a broader meaning than estriol:

estriol: a naturally occurring estrogenic hormone; a synthetic form is used to treat estrogen deficiency
oestrogen: a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics

Other hypernyms of estriol include estrogen.

estriol (noun)	oestrogen (noun)
a naturally occurring estrogenic hormone; a synthetic form is used to treat estrogen deficiency	a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics