n.
Pronunciation: ' es- ˌ tr ō n
Function: noun
Etymology: estrane
Date: 1933
: a natural estrogenic hormone that is a ketone C 18 H 22 O 2 found in the body chiefly as a metabolite of estradiol, that is also secreted especially by the ovaries, and that is used to treat various conditions (as ovarian failure and menopausal symptoms) relating to estrogen deficiency