Merriam-Webster Collegiate Dictionary - piracy

 noun  (plural -cies)  Etymology: Medieval Latin piratia, from Late Greek peirateia, from Greek peirates pirate  Date: 1537  1. an act of robbery on the high seas; also an act resembling such robbery  2. robbery on the high seas  3.  a. the unauthorized use of another's production, invention, or conception especially in infringement of a copyright  b. the illicit accessing of broadcast signals