Perl stands for Practical Extraction and Report Language, or (to its detractors, or its proponents on bad days), Pathologically Eclectic Rubbish Lister.
Perl was written by Larry Wall (who also wrote the news reader rn and the patch utility) and distributed for free under either of two open source licenses. It is supported both by a wide community of Perl programmers worldwide, and by commercial support organisations.
It is used for all kinds of programming, and has been ported to many systems. Perl interpreters are available for Unix, Windows, DOS, MacOS, and more.
Perl is intended to make easy things easy and hard things possible. With Perl, it is easy to start writing useful programs only minutes after first reading about it.