[ ˌmɪfɛ'prɪstəʊn ]
■ noun Medicine a synthetic steroid that inhibits the action of progesterone, given orally in early pregnancy to induce abortion.
Origin
1980s: prob. from Du. mifepriston , from mife- (representing aminophenol ) + -pr- (representing propyl ) + -ist- (representing oestradiol ) + -one .