What is the difference between multiprocessing, multiprogramming,multitasking and multithreading?

What is the difference between multiprocessing, multiprogramming,multitasking and multithreading?

Multitasking:
The ability to execute more than one task at the same time
Tasks sharing a common resource (like 1 CPU)
More than one task/program/job/process can reside into the same CPU at one point of time.
This ability of the OS is called multitasking.


Multiprogramming:
The allocation of a computer system and its resources to more than one concurrent application, job or user
A computer running more than one program at a time (like running Excel and Firefox simultaneously)
More than one task/program/job/process can reside into the main memory at one point of time.
This ability of the OS is called multiprogramming.

Multithreading:
Executing more than one thread parallely using a single processor

Multiprocessing:
Simultaneous execution of instructions by multiple processors within a single computer
A computer using more than one CPU at a time