Patch

A patch is data for modifying an existing software resource such as a program or a file, often to fix bugs and security vulnerabilities. To patch is also the process of applying the data to the existing resource. Patching a system involves applying a patch. A patch may be created to improve functionality, usability, or performance. A patch may be created manually, but commonly it is created via a tool that compares two versions of the resource and generates data that can be used to transform one to the other.