c.1300, pocioun "medicinal drink," from Old French pocion "potion, draught, medicine" (12c.), from Latin potionem (nominative potio) "a potion, a drinking," also "poisonous draught, magic potion," from potus, irregular past participle of potare "to drink," from PIE root *po(i)- "to drink" (cognates: Sanskrit pati "drinks," panam "beverage;" Greek pinein "to drink," poton "that which one drinks," potos "drinking bout;" Old Church Slavonic piti "to drink," pivo "beverage"). Potus as a past participle adjective in Latin meant "drunken."