1: an act of robbery esp. on the high seas
specif
: an illegal act of violence, detention, or plunder committed for private ends by crew or passengers of a private ship or aircraft against another ship or aircraft on the high seas or in a place outside the jurisdiction of any state
(see also aircraft piracy Article I of the Constitution in the back matter)
2 a: the unauthorized copying, distribution, or use of another's production (as a film) esp. in infringement of a copyright
Example: software piracy
b: the unauthorized use, interception, or receipt of encoded communications (as satellite cable programming) esp. to avoid paying fees for use
Example: the statute's purpose is to proscribe the piracy of programming signals -- United States v. Harrell, 983 F.2d 36 (1993)
3: the crime of committing piracy