CASTANETS, instruments of percussion, introduced through the Moors by way of Spain into Europe from the East. Cas tanets, always used in pairs, one in each hand, consist of two pear or mussel-shaped bowls of hard wood, hinged together by a cord, the loop being passed over the thumb and first finger. The two halves are struck against each other by the other fingers giving out a series of hollow clicks of indefinite musical pitch. Castanets were used by the ancient Greeks, and also by the Romans to ac company the dances in the Dionysiac and Bacchanalian rites.