A term applied rather loosely to a number of rather similar concepts but with important detailed differences. The essence of parallel processing is that more than one particular process is active at any given instant; however the term is often applied to a situation in which a large number of processes are potentially active but at any one instant only one is active. Strictly speaking the term parallel processing should only be applied where more than one processor is active among a group of processes at any one instant. In practice it is seldom used with this accurate connotation. See also concurrent programming.