Noise

Noise, in physics, an acoustic, electrical, or electronic signal consisting of a random mixture of wavelengths (see Sound). In information theory, the term designates a signal that contains no information. In acoustics, “white” noise consists of all audible frequencies, just as white light consists of all visible frequencies. Noise is also a subjective term, referring to any unwanted sound. Noise pollution (see Aeroplane) is a serious environmental problem, particularly as sound levels above a certain intensity can be physically damaging.