Feedback is a process in which information about the output of a system is used to modify the next input to the system. Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The loop may be direct, as when sound from a loudspeaker is picked up by a microphone and amplified again; or it may be indirect, such as when blood sugar levels affect insulin production.
In biology, feedback mechanisms play an important role in homeostasis, maintaining conditions such as blood pressure and temperature within safe limits. In engineering, feedback is essential for controlling dynamic systems such as vehicle steering and aircraft stabilization.
The term “feedback” was first used in cybernetics by Norbert Wiener (1948). It comes from the Latin word “recuperare” meaning “to regain” or “to recover.”