The name of an open source programming language created and distributed by Larry Wall. It is widely used to write programs in a platform independent way. It is likely the most common language in use today for writing web based applications, probably because of it's ability to run programs without modification on just about every platform known in the free world. It is not limited to web based applications though.

Perl is commonly thought to be an abbreviation for Practical Extraction and Report Language and sometimes believed to be an abbreviation for Pathologically Eclectic Rubbish Lister (the latter being preferred by its creator).

The source code for Perl is freely available, so it can be compiled to run on the platform of your choice. Many people have compiled the source code on their favorite platforms (like Windows, Linux, AS/400, Apple, etc) and have made the resulting Perl executables (called ports or binaries in the open source world) available for download.

For a full list of all the platforms Perl has been ported to, along with links to download them, see the CPAN web site.