Thread

A thread is a set of instructions, designed to be executed independently from the parent process.

PHP supports threads with extensions, such as the pthread extension. It also supports a thread safe compilation version: it allows PHP to be used with threaded web servers.

Documentation

See also pthreads, What does thread safety mean when downloading PHP? and PHP and Threads.

Related : Process, Async, Asynchronous, Multithreading, Concurency