Acousmatic sound is sound one hears without seeing an originating cause. The word acousmatic, from the French acousmatique, is derived from the Greek word akousmatikoi (ἀκουσματικοί), a term used to refer to probationary pupils of the philosopher Pythagoras who, so that they might better concentrate on his teachings, were required to sit in absolute silence while listening to their teacher deliver his lecture from behind a veil or screen. The term acousmatique was first used by the French composer and pioneer of musique concrète Pierre Schaeffer. In acousmatic art one hears sound from behind a "veil" of loudspeakers, the source cause remaining unseen. More generally, any sound, whether natural or manipulated, may be described as acousmatic if the cause of the sound remains unseen. The term