Jetsam of 1773 refers to the Boston TEA Party, an event that occurred on December 16th, 1773 in which American colonists, disguised as Native Americans, boarded three ships in Boston Harbor and threw 342 chests of TEA into the harbor as a protest against the British government's taxation of the colonies without their consent. The term 'jetsam of 1773' is used to refer to the TEA that was thrown overboard. The crossword solution for this term is TEA, which is a three-letter word.