castanets <p>Concussion instruments consisting of a pair of small shallow cup-shaped pieces of hardwood, strung together, hollow sides facing each other, on a cord which loops around the player's thumb. The two pieces are clicked together by the fingers. Usually two pairs are played together, one higher-pitched than the other.</p> <p>Source: Art &amp; Architecture Thesaurus</p> <p>http://vocab.getty.edu/page/aat/300041917</p>