Copyright is a legal protection in many countries that gives the creator of original works the exclusive right to determine the conditions under which their work can be used by others. Depending on the jurisdiction, the creator may be required to follow a process to establish copyright, or may be granted copyright automatically on any creative work without any registration required. The right typically will expire a designated number of years after the creator has died.
Copyright was designed to protect and incentivize literary and artistic creation, but has expanded to regulate the copying of things like recordings, films, photographs, and software.
The rights generally protected by copyright make sure that the creator/owner is the only one who can distribute, reproduce, perform, or display the work, or create derivative works from it. The holder of a copyright is free to sell, lend, modify, or even destroy the work, but no one else may do so without their permission, often granted by purchasing it. By contrast, the copyleft software license allows anyone to freely use, distribute, and modify the software, as long as they make their derivative work similarly free to others.