Unix Tools - What is Processes

Process is kind of program or task carried out by your PC. For e.g.
$ ls -lR
ls command or a request to list files in a directory and all subdirectory in your current directory - It is a process.
Process defined as:
"A process is program (command given by user) to perform specific Job. In Linux when you start process, it gives a number to process (called PID or process-id), PID starts from 0 to 65535."