castanets

(used in the plural) a percussion instrument consisting of a pair of hollow pieces of wood or bone (usually held between the thumb and fingers) that are made to click together (as by Spanish dancers) in rhythm with the dance

（複数形で）一対のくぼんだ木片または骨片からなり、（通常は親指と指の間に挟んで持ち）踊りのリズムに合わせて（スペインの踊り手のように）打ち鳴らされる打楽器