late 14c., digestioun, "conversion of food to a state in which it can be absorbed into the blood from the alimentary canal," from Old French digestion (13c.) and directly from Latin digestionem (nominative digestio) "digestion, arrangement," noun of action from past-participle stem of digerere "to separate, divide, arrange," etymologically "to carry apart," from dis- "apart" (see dis-) + gerere "to carry" (see gest).