PHP, short for Hypertext Preprocessor, is a server-side scripting language that drives many of the websites around the world behind the scenes.
PHP runs completely server-side. That means that most common users of the Internet will never actually interact directly with a PHP script.
The code is interpreted by the server using a module. The server then performs the requested instructions and returns the desired output, if there is one, for the server to display for visitors.
PHP takes its inspiration from Perl, C, C++ and Java. It carries the pragmatic, easy-to-use nature of a scripting language like Perl, name declarations like those found in C, the speed of C++ programs and the polymorphism allowed by Java classes.
Compared to other forms of programming available for web servers to use, PHP is toted as being one of the fastest. When used responsibly, it can also be one of the safest and secure, which is a feat considering that it is a language that is released as free software and used in a way that is almost compliant with the GNU General Public License.
PHP is commonly paired with MySQL, a powerful type of database software that is used for storing data.