The acronym LAMP (or L.A.M.P.) refers to a set of free software programs commonly used together to run dynamic Web sites or servers:
Since these environments now also run on other OSs, one often uses the generic AMP acronym.
According to O'Reilly manager Dale Dougherty: “... in 2001, David Axmark and Monty Widenius of the MySQL team visited us in Sebastopol and they dropped a new term in our laps: LAMP. This term was popular in Germany, they said, to define how MySQL was used in conjunction with Linux, Apache, and either Perl, Python, or PHP. Their explanation of LAMP made a lightbulb go off in my head.”
There are of course other variants of bundles, see the Wikipedia LAMP article
See also WAMP, the equivalent for Windows. It also contains some information on how to run a local copy of your MediaWiki on your travel PC.