castanetyoudaoicibaDictYouDict
castanet: [17] Castanets were originally named in Spanish from their resemblance to the shells of chestnuts, Spanish castañeta being a diminutive form of castaña ‘chestnut’, from Latin castanea (itself the ultimate source of English chestnut). Another name for them in 17th-century English was knackers: ‘Castinettas: knackers of the form of chestnuts, used to this day by the Spaniards in their dances’, Robert Stapylton, Juvenal’s sixteen satires 1647.
=> chestnut
castanet (n.)youdaoicibaDictYouDict
usually castanets, 1640s, from French castagnette or directly from Spanish castañeta diminutive of castaña "chestnut," from Latin castanea (see chestnut).
castanetsyoudaoicibaDictYouDict
"Small concave pieces of wood, ivory, or plastic, joined in pairs by a cord and clicked together by the fingers as a rhythmic accompaniment to Spanish dancing", Early 17th century: from Spanish castañeta, diminutive of castaña, from Latin castanea 'chestnut'.