Flexible stick with horsehair (usually) stretched across it, used to produce sound vibrations from strings of vn., va., vc., db., and other str. instr. Until 17th cent. bow was convex. As vn. technique developed, new forms of concave bow were devised, with hairs kept in place and at an even spread by means of metal ferrule through which hair passed as it left the nut, or ‘frog’ at one end of the bow. Prin. developer of modern bow was François Tourte, c.1785.