An open system is a feedforward system that does not have any feedback loop to control its output in a control system in systems theory. The system is an "open" system because it does not have a feedback loop in its control. In contrast, a closed system uses on a feedback loop to control the operation of the system. In an open system, the output of this system is not fed back into the input to the system for control or operation. An open system is essentially a feedforward system. Feed-forward is a term describing a kind of system which reacts to changes in its environment, usually to maintain some desired state of the system. ... System (from the Latin (systēma), and this from the Greek (sustēma)) is an assemblage of entity/objects, real or abstract, comprising a whole with each and every component/element interacting or related to another one. ... In cybernetics and control theory, feedback is a process whereby some proportion or in general, function, of the output signal of a system is passed (fed back) to the input. ... It has been suggested that this article or section be merged with Control theory. ... Systems theory is an interdisciplinary/multiperspectual field of inquiry that studies the theoretical and actual properties of systems as a process by looking at it in terms of relationships from which emerge new properties of wholes. ... A closed system is a system which relies on a feedback loop to control its output in a control system in systems theory. ...