[pro.lapse] n [NL prolapsus, fr. LL, fall, fr. L prolabi to fall or slide forward, fr. pro- forward + labi to slide--more at pro-, sleep] (ca. 1834): the falling down or slipping of a body part from its usual position or relations
[2]pro.lapse vi pro.lapsed ; pro.laps.ing (1876): to undergo prolapse