PHP (Hypertext Preprocessor) is a widely-used open-source server-side scripting language designed for web development. PHP code is executed on the server, generating HTML that is sent to the client. It’s known for its ease of use, flexibility, and support for various databases.

Originally, PHP stood for "Personal Home Page." Now it stands for "PHP: Hypertext Preprocessor," which is a recursive acronym.

You can install PHP by downloading it from php.net, or you can use bundled software like XAMPP, WAMP (for Windows), or MAMP (for Mac). These packages include PHP, a web server (Apache), and a database (MySQL) for an easy setup.