RU 486 ru uncommon noun 1. an abortion-inducing drug (trade name Mifepristone) developed in France; when taken during the first five weeks of pregnancy it blocks the action of progesterone so that the uterus sloughs off the embryo Synonymsabortion pillRU 486Mifepristone Related words Broader terms abortifacient WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
