Noise

In common use the word noise means random, irregular, unwanted signals that appear and partially mask desired signals such as acoustic noise in an audio system or “snow” in a degraded television or video image. In signal processing or computing it can be considered data without meaning, i.e., data that is not being used to convey information, but is simply produced as an unwanted byproduct of other activities. Signal-to-noise ratio is often computed to indicate the quality of the information.