A more thorough explanation:

Definition: Copyleft is a type of software license that allows users to modify or use open-source code in their own programs, as long as the resulting software is also open-source and freely available to the public.

Example: The GNU General Public License (GPL) is a popular copyleft license used for many open-source software projects. It allows users to modify and distribute the software, but requires that any changes made to the code are also made available to the public under the same license.

Explanation: Copyleft licenses like the GPL are designed to promote collaboration and sharing within the open-source community. By allowing users to freely modify and distribute open-source code, copyleft licenses help to create a culture of innovation and cooperation, where developers can build on each other's work to create better software for everyone.