PHP (Hypertext Preprocessor) is a server-side scripting language designed for web development. It was created by Rasmus Lerdorf in 1994 and is now maintained by the PHP Group.

PHP is a widely-used open-source language that can be embedded in HTML, allowing developers to create dynamic web pages and web applications. It is also commonly used for command-line scripting and can be used to develop desktop applications as well.

PHP is compatible with almost all servers and operating systems and supports a wide range of databases, including MySQL, PostgreSQL, Oracle, and Microsoft SQL Server. Its syntax is similar to C and Perl, making it easy to learn for programmers familiar with those languages.

Some of the key features of PHP include its ability to handle form data, interact with databases, generate dynamic content, and create sessions for user login and authentication. It also has a large community of developers who contribute to its development and maintenance, ensuring that it remains up-to-date and secure.

Overall, PHP is a powerful and flexible language that is widely used for web development due to its ease of use, versatility, and compatibility with a range of technologies.