Meaning of acoustic feedback

acous'tic feed'back

Pronunciation: [key]
— Electronics. Electronics.
  1. (in an audio system, esp. a public-address system) the feedback of sound from a loudspeaker to a microphone, often resulting in a whistling noise caused by electrical oscillations. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.