—n. 1. a person who robs or commits illegal violence at sea or on the shores of the sea.
2. a ship used by such persons.
3. any plunderer, predator, etc.: confidence men, slumlords, and other pirates. 4. a person who uses or reproduces the work or invention of another without authorization.
5. Also called pi'rate stream".Geol.a stream that diverts into its own flow the headwaters of another stream, river, etc.
—v.t. 1. to commit piracy upon; plunder; rob.
2. to take by piracy: to pirate gold. 3. to use or reproduce (a book, an invention, etc.) without authorization or legal right: to pirate hit records. 4. to take or entice away for one's own use: Our competitor is trying to pirate our best salesman.