Short for PHP Extension and Application Repository, PEAR is a framework and distribution system for reusable PHP components. PEAR is a community-driven project with the PEAR Group as the governing body. The project was founded by Stig S. Bakken in 1999.
The code in PEAR is partitioned in packages, where each package is a separate project with its own development team, version number, release cycle, documentation and a defined relation to other packages (including dependencies). Packages are distributed as gzipped tar files with a description file inside, and installed on your local system using the PEAR installer. There are two types of packages: source packages (containing source files only), and binary packages (containing platform-specific binary files, and possible source files). [Source: PEAR Manual]