- jettison (v.)
- 1848, "to throw overboard," especially to save a ship in danger, from jettison (n.) "act of throwing overboard" to lighten a ship. This noun was an 18c. Marine Insurance writers' restoration of the earlier form and original sense of the 15c. word that had become jetsam, probably because jetsam had taken on a sense of "things cast overboard" and an unambiguous word was needed for "act of casting things overboard."
Middle English jetteson (n.) "act of throwing overboard" is from Anglo-French getteson, Old French getaison "act of throwing (goods overboard)," especially to lighten a ship in distress, from Late Latin iactionem (nominative iactatio) "a throwing, act of throwing," noun of action from past participle stem of iactare "to throw, toss about" (see jet (v.1)). Related: Jettisoned.