A Thread or a “Thread of Execution” is defined as the smallest unit that can be scheduled in an operating system.
Threads are normally created by a fork of a computer script or program in two or more parallel tasks.
Threads are usually contained in processes.
More than one thread can exist within the same process. These threads share the memory and the state of the process, i.e. they share the code or instructions and the values of its variables.
There are two different kinds of threads:
Kernel Threads are part of the operating system, while User-space threads are not implemented in the kernel.