Definify.com
Webster 1913 Edition
Castanets
Cas′ta-nets
,Noun.
pl.
[F.
castagnettes
, Sp. castañetas
, fr. L. castanea
(Sp. castaña
) a chestnut. So named from the resemblance to two chestnuts, or because chestnuts were first used for castanets. See Chestnut
.] Two small, concave shells of ivory or hard wood, shaped like spoons, fastened to the thumb, and beaten together with the middle finger; – used by the Spaniards and Moors as an accompaniment to their dance and guitars.
☞ The singular, castanet, is used of one of the pair, or, sometimes, of the pair forming the instrument.
The dancer, holding a
castanet
in each hand, rattles them to the motion of his feet. Moore (Encyc. of Music).