Definition of "piracy"

(nautical) Robbery at sea, a violation of international law; taking a ship away from the control of those who are legally entitled to it.  examples

A similar violation of international law, such as hijacking of an aircraft.  examples

The unauthorized duplication of goods protected by intellectual property law.  examples

The operation of an unlicensed radio or television station.  examples

(ornithology) Kleptoparasitism.