1. A robber on the high seas; one who by open violence takes the property of another on the high seas; especially, one who makes it his business to cruise for robbery or plunder; a freebooter on the seas; also, one who steals in a harbor.
2. An armed ship or vessel which sails without a legal commission, for the purpose of plundering other vessels on the high seas.
3. One who infringes the law of copyright, or publishes the work of an author without permission.
(Science: zoology) Pirate perch, a fresh water percoid fish of the united states (Aphredoderus Sayanus). It is of a dark olive colour, speckled with blackish spots.
Origin: L. Pirata, Gr, fr. To attempt, undertake, from making attempts or attacks on ships, an attempt, trial; akin to E. Peril: cf. F. Pirate. See Peril.