Pronunciation: (es'trōn),[key] —n. 1. Biochem.an estrogenic hormone, C18H22O2, produced by the ovarian follicles and found during pregnancy in urine and placental tissue.
2. Pharm.a commercial form of this compound, obtained from the urine of pregnant women or synthesized from ergosterol, used in the treatment of estrogen deficiency and certain menopausal and postmenopausal conditions. Also,estrin.