Thread

A thread in computer science is short for a thread of execution. Threads are a way for a program to fork (or split) itself into two or more simultaneously (or pseudo-simultaneously) running tasks. Threads and processes differ from one operating system to another but, in general, a thread is contained inside a process and different threads in the same process share some resources while different processes do not.
On a single processor, Multithreading generally occurs by time-division multiplexing ("time slicing") in very much the same way as the parallel execution of multiple tasks (computer multitasking): the processor switches between different threads. This context switching can happen so fast as to give the illusion of simultaneity to an end user. On a multiprocessor or multi-core system, threading can be achieved via multiprocessing, wherein different threads and processes can run literally simultaneously on different processors or cores.