The study and modeling of communication, regulation and control in systems. (Wiener 1948)
Wiener, N. 1948. Cybernetics: or Control and Communication in the Animal and the Machine. Cambridge, MA, USA: The Massachusetts Institute of Technology Press.
Cybernetics studies the flow of information through a system and how information is used by the system to control itself through feedback mechanisms. Early work in cybernetics in the 1940 was applied to electronic and mechanical networks, and was one of the disciplines used in the formation of early systems theory. It has since been used as a set of founding principles for all of the significant system disciplines.