jetsam

Jetsam comes from the Anglo-French jetteson, from Old French jeter (to throw), from Latin jactare (to throw repeatedly). The word named a specific maritime legal category: goods that were deliberately thrown overboard (jettisoned) to lighten a ship in danger of sinking. The act was calculated — the captain chose what to sacrifice so the rest might survive. Jetsam was not accident but decision.

Maritime law treated jetsam differently from flotsam because the act of jettisoning was intentional. If a ship survived and its jettisoned cargo washed ashore, the original owner could claim it. This was different from flotsam (accidental wreckage), which belonged to the Crown. The legal reasoning was that a captain who saved his ship by sacrificing cargo should not also lose ownership of what he threw away. The word encoded a moral judgment: intentional sacrifice was treated differently from accidental loss.

The concept of jettisoning — throwing goods overboard to save the vessel — led to the legal principle of 'general average,' one of the oldest principles in maritime law. If cargo was jettisoned to save the ship, all parties with cargo aboard shared the loss proportionally. A merchant whose goods survived paid a portion of the value of goods that were thrown overboard. The word jetsam was the foundation of maritime insurance law.

English generalized the verb: to jettison now means to discard anything to lighten a load or improve a situation. You can jettison a failing strategy, jettison a relationship, jettison your plans. The maritime specificity has dissolved. But the original word carried a weight that the general usage has lost. Jetsam was not trash. It was the cargo you loved that you threw into the sea because the alternative was everyone drowning.