PHP is a widely-used open-source scripting language primarily designed for web development. It is embedded within HTML and works on the server side, enabling dynamic content generation, session management, and database interaction. PHP is known for its simplicity, flexibility, and large community support. It powers popular content management systems like WordPress, Joomla, and Drupal, and integrates well with databases such as MySQL and PostgreSQL. PHP supports object-oriented programming, and its vast library of functions and frameworks like Laravel and Symfony make it a versatile choice for building web applications of varying complexity.