早在15世纪，“海上抢劫，指在公海上进行抢劫的行为”，这个词源于中世纪拉丁语 piratia，而其更早的来源则是古典拉丁语和希腊语中的 peirateia，意为“海盗行为”，来自 peiratēs，意指“强盗，海盗”（参见 pirate (n.)）。
Specifically, in the l aw of nations, the crime of depredations or wilful and aggressive destruction of life or property committed on the seas by persons having no commission or authority from any established state. As commonly used it implies something more than a simple theft with violence at sea, and includes something of the idea of general hostility to law. According to the opinion of some, it implies only unlawful interference with a vessel ; according to others, it includes also depredations on the coast by a force landing from the sea. [Century Dictionary]
在国际法中，海盗特指那些在海上进行掠夺或故意、侵略性地破坏生命和财产的犯罪行为。这些行为是由没有任何国家授权或委任的人所实施的。通常来说，这个词不仅仅指在海上暴力抢劫，还包含了对法律的普遍敌视。有些人认为，它仅仅意味着对船只的非法干扰；而另一些人则认为，它还包括从海上登陆后对沿海地区的掠夺行为。[世纪词典]
