castanet/ˌkæs.təˈnɛt/EtymologyFrom Spanish castañeta, diminutive form of castaña, from Latin castanea, from Ancient Greek καστάνεια (kastáneia, “chestnut”), possibly of Pre-Greek origin. Related to the chest in chestnut, formerly chesten.castanet means A single handheld percussion instrument consisting of a pair of concave shells or shell-shaped parts joined on one edge by string. Lexicurio rates it Sui generis — a strength score of 90 out of 100.nounA single handheld percussion instrument consisting of a pair of concave shells or shell-shaped parts joined on one edge by string.