oestriol vs estriol

oestriol and estriol both are nouns.

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

As nouns, oestriol and estriol are synonyms defined as:

oestriol and estriol: a naturally occurring estrogenic hormone; a synthetic form is used to treat estrogen deficiency

oestriol (noun)	estriol (noun)
a naturally occurring estrogenic hormone; a synthetic form is used to treat estrogen deficiency	a naturally occurring estrogenic hormone; a synthetic form is used to treat estrogen deficiency