[feed.back] n (1920) 1: the return to the input of a part of the output of a machine, system, or process (as for producing changes in an electronic circuit that improve performance or in an automatic control device that provide self-corrective action)
2. a: the partial reversion of the effects of a process to its source or to a preceding stage b: the transmission of evaluative or corrective information to the original or controlling source about an action, event, or process; also: the information so transmitted