Many scholars argue that a major obstacle to eradicating the global problem of maritime piracy is the lack of a uniform definition of piracy. Their chief concern is that without a uniform definition, it is difficult to formulate responses on a systemic and global level. This article contends that having multiple definitions of piracy for different purposes is conducive to combating piracy and addressing the ensuing legal issues. While uniformity between certain definitions should be pursued, complete uniformity should not be adopted due to the multiple purposes the definition of piracy serves. This article categorises the definition of maritime piracy according to four respective purposes: public international law, domestic criminal law, commercial law, and piracy prevention. It demonstrates that uniformity is important between the first two purposes due to the need to uphold rule of law principles. However, this definition should not be uniform with regard to the definitions for the last two purposes due to the need for flexible and expansive definitions in commercial law and piracy prevention.