PHP is a server-side scripting language used for web development. It stands for “PHP: Hypertext Preprocessor” and is widely used for building dynamic websites, web applications, and web services. PHP code is executed on the server, and the output is sent to the client’s web browser as HTML.

Some key features of PHP include:

1. Dynamically typed: PHP does not require explicit variable declaration and supports dynamic typing, allowing for flexibility in coding.
2. Embeddable: PHP code can be embedded within HTML code, making it easy to integrate dynamic content into web pages.
3. Extensive library support: PHP has a large standard library and a wide range of third-party libraries, making it easy to add functionality to web applications.
4. Database support: PHP provides built-in support for working with databases, including MySQL, SQLite, and PostgreSQL, allowing for easy database integration in web applications.
5. Server-side scripting: PHP is a server-side scripting language, which means that it runs on the server and generates dynamic content that is sent to the client’s web browser as HTML.
6. Open source: PHP is an open-source language, which means that its source code is freely available, and it has a large community of developers who contribute to its development and provide support.
7. Cross-platform compatibility: PHP is cross-platform compatible, meaning it can run on different operating systems, including Windows, macOS, Linux, and others.

PHP is widely used in web development due to its ease of use, flexibility, and extensive community support. It is commonly used in popular content management systems (CMS) like WordPress, Drupal, and Joomla, as well as in custom web applications and web services.