FEEDBACK

(RETURN) [noun] [U] - the return of part of what a machine or system produces back into the machine or system, esp. to improve what is produced, or the sudden, high, unpleasant noise sometimes produced by an amplifier when sound it produces is put back into itFeedback from the sensors ensures that the car engine runs smoothly.Jimi Hendrix loved to fling his guitar around to get weird and wonderful sounds from the feedback.