Copyright infringement (at times referred to as piracy) is the use of works protected by copyright without permission for a usage where such permission is required, thereby infringing certain exclusive rights granted to the copyright holder, such as the right to reproduce, distribute, display or perform the protected work, or to make derivative works. The copyright holder is typically the work's creator, or a publisher or other business to whom copyright has been assigned. Copyright holders routinely invoke legal and technological measures to prevent and penalize copyright infringement.

Copyright infringement disputes are usually resolved through direct negotiation, a notice and take down process, or litigation in civil court. Egregious or large-scale commercial infringement, especially when it involves counterfeiting, is sometimes prosecuted via the criminal justice system. Shifting public expectations, advances in digital technology and the increasing reach of the Internet have led to such widespread, anonymous infringement that copyright-dependent industries now focus less on pursuing individuals who seek and share copyright-protected content online, and more on expanding copyright law to recognize and penalize, as indirect infringers, the service providers and software distributors who are said to facilitate and encourage individual acts of infringement by others.

Estimates of the actual economic impact of copyright infringement vary widely and depend on other factors. Nevertheless, copyright holders, industry representatives, and legislators have long characterized copyright infringement as piracy or theft – language which some U.S. courts now regard as pejorative or otherwise contentious.

Terminology.

The terms piracy and theft are often associated with copyright infringement. The original meaning of piracy is "robbery or illegal violence at sea", but the term has been in use for centuries as a synonym for acts of copyright infringement. Theft, meanwhile, emphasizes the potential commercial harm of infringement to copyright holders. However, copyright is a type of intellectual property, an area of law distinct from that which covers robbery or theft, offenses related only to tangible property. Not all copyright infringement results in commercial loss, and the U.S. Supreme Court ruled in 1985 that infringement does not easily equate with theft.

This was taken further in the case MPAA v Hotfile, where Judge Kathleen M Williams granted a motion to deny the MPAA the usage of words whose appearance was primarily "pejorative". This list included the word "piracy", the use of which, the motion by the defense stated, serves no court purpose but to misguide and inflame the jury.