LAMP is an acronym for a solution stack of free, open source software, originally coined from the first letters of Linux (operating system), Apache HTTP Server, MySQL (database software) and Perl/PHP/Python, principal components to build a viable general purpose web server.
The exact combination of software included in a Linux, Apache, MySQL and PHP (LAMP) package may vary, especially with respect to the web scripting software, as PHP may be replaced or supplemented by Perl and/or Python. Similar terms exist for essentially the same software suite (AMP) running on other operating systems, such as Microsoft Windows (WAMP), Mac OS (MAMP), Solaris (SAMP), or OpenBSD (OAMP).
Though the original authors of these programs did not design them all to work specifically with each other, the development philosophy and tool sets are shared and were developed in close conjunction. The software combination has become popular because it is free of cost, open-source, and therefore easily adaptable, and because of the ubiquity of its components which are bundled with most current Linux distributions.
When used together, they form a solution stack of technologies that support application servers.