PHP is a web scripting language that has been around for over ten years now.  It is by far the most popular open source web scripting language.  PHP has very powerful features for creating dynamic web content.  When teamed up with MySQL, PHP can accomplish anything with the web that other non-open source solutions can, and without the upfront licensing fees!

PHP stands for PHP Hypertext Pre-processor.  It originally stood for Personal Home Page, however that didn't seem professional enough for large enterprises to take notice of.  So the name was change to a more absured definition.