1. In Communication, this is any interference with a communication’s clarity or accuracy. Superfluous message data or words are noise as they detract from the message’s meaning. 2. In Quality control, this is the variability in ambient conditions, faulty machine performance, or uneven material quality or human factor inputs. 3. In Telecommunications, this is random disturbance becoming part of a communication signal, due to circuit components, electromagnetic interference, or weather conditions. Also known as line noise.