What Does Feedback Mean?

Feedback refers to the return of some part of the output of a certain process back into the input, the purpose being the controlling or the maintaining of performance of the system at a particular level.

In terms of acoustics feedback refers to the sound that is formed as a result of the microphone or electric guitar picking up the resultant sound from the speakers and then re channelling these through the system back out through the amplifiers.

In a biological or ecological sense it refers to the process with the help of which the system gets affected, changed, modulated or controlled by the response or output that it produces.  

An example of how a feedback works is when at the end of some seminar, car servicing process, banking transaction etc a feedback form is given to the customer to provide insights into their opinion of the quality and performance of the product or system and thereby take corrective measures if necessary.