mifepristone

American

[mif-uh-pris-tohn] / ˌmɪf əˈprɪs toʊn /

noun

an antigestational drug, C 29 H 35 NO 2 , that prevents a fertilized egg from attaching to the uterine wall by blocking the action of progesterone.

mifepristone British

/ mɪˈfɛprɪˌstəʊn /

noun

an antiprogestogenic steroid, used in the medical termination of pregnancy. Formula: C 29 H 35 NO 2

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of mifepristone

1985–90; probably alteration of (a)mi(no)phe(nol) + pr(opyl) + est(radiol) + -one

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The FDA website currently says that mifepristone, approved decades ago, is safe to use as indicated.

From The Wall Street Journal • Jun. 5, 2026

Former FDA Commissioner Marty Makary, ousted last month, had promised lawmakers he would launch a mifepristone study but told others in the administration that he needed new data systems for the effort.

From The Wall Street Journal • Jun. 5, 2026

On this week’s Amicus, Dahlia Lithwick and Mark Joseph Stern dive into the legal battle over mifepristone, the medication that can be used for abortion care.

From Slate • May 21, 2026

If mifepristone is difficult to obtain, a misoprostol-only medication abortion still works.

From Salon • May 15, 2026

Danco Laboratories and GenBioPro, which manufacture mifepristone, asked the Supreme Court to pause the appeals court order while they prepare to bring an emergency case to the top court.

From Barron's • May 14, 2026

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023