This plural noun is the name of a percussion instrument consisting of round pieces of shell, wood, or bone held in the fingers. Castanets were originally made from chestnuts and get their name from the Spanish diminutive for chestnut. Like drums, shakers, and other percussion instruments, castanets help create the rhythm in a piece of music. Castanets tend to be part of rhythmically lively music that makes people want to dance. Castanets are also called bones, clappers, and finger cymbals.