Shoulder Rest

In music, a bow /boʊ/ is a tensioned stick which has hair (usually horse-tail hair) coated in rosin (to facilitate friction) affixed to it. It is moved across some part of a musical instrument to cause vibration, which the instrument emits as sound. The vast majority of bows are used with string instruments, such as the violin, although some bows are used with musical saws and other bowed idiophones.