WordNet sense 1 (a potent estrogen used in medicine and in feed for livestock and poultry):

diethylstilbestrol, diethylstilboestrol, stilbestrol, stilboestrol

WordNet sense 2 (synthetic nonsteroid with the properties of estrogen; formerly used to treat menstrual problems but was found to be associated with vaginal cancers in the daughters of women so treated during pregnancy):

diethylstilbesterol, stilbesterol