PHP Engine
The PHP engine, often referred to as the PHP interpreter, is the core component of the PHP programming language. It is responsible for translating and executing PHP code on a web server or other environments that support PHP. The engine takes the human-readable PHP code and converts it into machine-level instructions that the computer can understand and execute.
It is also called the php binary, or the PHP executable, although these names refer to the engine while its running, in a production or operating system environment.