c. 1400, prostracioun, "action of prostrating oneself" (in humility, adoration, etc.), from Old French prostracion (14c.) and directly from Late Latin prostrationem (nominative prostratio) "an overthrowing, a subverting," noun of action from past-participle stem of prosternere "strew in front, throw down" (see prostrate (v.)); or else a native formation from prostrate (v.). Meaning "weakness, exhaustion" is from 1650s; by early 19c. also "dejection, depression of spirits."