<p><strong>Noun</strong></p><ul><li>A nonsteroidal synthetic estrogen, C18H20O2, used in medicine chiefly in the treatment of menopausal symptoms and for chemical castration.</li><li>Formerly used during pregnancy for the prevention of miscarriage but discontinued owing to its association with an increased risk of vaginal and cervical cancers.</li><li>Also known as DES.</li></ul>