Are yams and sweet potatoes the same?
1560s, jottsome "act of throwing goods overboard to lighten a ship," alteration and contraction of Middle English jetteson, from Anglo-French getteson, Old French getaison "a throwing" (see jettison). Intermediate forms were jetson, jetsome; the form perhaps was deformed by influence of flotsam. From 1590s as "goods thrown overboard;" figurative use by 1861. For distinction of meaning, see flotsam.