The flute is a family of musical instruments in the woodwind group. Unlike woodwind instruments with reeds, a flute is an aerophone or reedless wind instrument that produces its sound from the flow of air across an opening. According to the instrument classification of Hornbostel–Sachs, flutes are categorized as edge-blown aerophones. Flutes are the earliest extant musical instruments. Flutes, including the famous Bansuri, have been an integral part of Indian classical music.