Selective Estrogen-Receptor Modulator (SERM)
A 'designer estrogen' which possesses some, but not all, of the actions of estrogen.
For example, raloxifene (trade name EVISTA) is classified as a SERM because it prevents bone loss (like estrogen) and lowers serum cholesterol (like estrogen) but (unlike estrogen) does not stimulate the endometrial lining of the uterus