PHP is a popular server-side scripting language used for creating dynamic and interactive web pages. It stands for Hypertext Preprocessor and is widely used for developing websites, web applications, and content management systems. It is an open-source language, meaning it is free to use and constantly evolving with contributions from a large community of developers. PHP is known for its flexibility, ease of use, and compatibility with various databases and web servers. It also offers a wide range of built-in functions and libraries, making it a powerful tool for creating dynamic and feature-rich websites.