pro·ges·to·gen noun alsopro·ges·ta·gen\prōˈjestəjə̇n, -ˌjen\ (-s) Etymology:progestational + -ogen (as in estrogen) or -agen (by alteration) : any of several progestational steroids (as progesterone or norethindrone) • pro·ges·to·gen·ic\prōˌjestəˈjenik, -ēk \adjective