Source : Webster's Revised Unabridged Dictionary (1913)

Piracy \Pi"ra*cy\, n.; pl. {Piracies}. [Cf. LL. piratia, Gr. ?.
   See {Pirate}.]
   1. The act or crime of a pirate.

   2. (Common Law) Robbery on the high seas; the taking of
      property from others on the open sea by open violence;
      without lawful authority, and with intent to steal; -- a
      crime answering to robbery on land.