cas·ta·net 
(kăs′tə-nĕt)
(kăs′tə-nĕt)n.
often castanets A percussion instrument consisting of a pair of slightly concave shells of ivory or hardwood, held in the palm of the hand by a connecting cord over the thumb and clapped together with the fingers.
[Spanish castañeta, from castaña, chestnut, from Latin castanea; see CHESTNUT.]
castanet