The word acousmatic comes from the Greek word akousma/akousmatikoi, which referred to students of the philosopher Pythagoras who, according to the legend, had to listen to him give lectures from behind a veil or screen to help them focus better on his teachings. The term acousmatique was first used by the French composer and pioneer of musique concrète, Pierre Schaeffer. In acousmatic art, one hears sound coming from behind a "veil" of loudspeakers, with the source remaining unseen. More generally, any sound, whether natural or manipulated, can be described as acousmatic if the source of the sound remains hidden.