PHP stands for PHP: Hypertext Preprocessor. This confuses many people because the first word of the acronym is the acronym. This type of acronym is called a recursive acronym.
PHP is an HTML-embedded scripting language. Much of its syntax is borrowed from C, Java and Perl with a couple of unique PHP-specific features thrown in.
The goal of the language is to allow web developers to write dynamically generated pages quickly.
Much like its competitors, PHP is used primarily for writing Web-based applications that require some sort of access to a database.
Bulletin Boards / Forums, E-commerce(shopping carts), HR / Customer details databases etc.