From Longman Dictionary of Contemporary Englishcastanetscas‧ta‧nets /ˌkæstəˈnets/ noun [plural] 
APMa musical instrument made of two small round pieces of wood or plastic that you hold in one hand and knock together, used especially by Spanish dancers
APMa musical instrument made of two small round pieces of wood or plastic that you hold in one hand and knock together, used especially by Spanish dancersExamples from the Corpus
castanets• The jacaranda pods were too stiff to act as castanets.• I clattered down the street-my heels noisy as castanets on the kerb-through to the market.• Fine, dry nights were accompanied by the sound of wild pea pods clacking like castanets.• With the tip of her painted fingernail, the dancer salesgirl showed the miniature castanets the doll was holding.• If I'd had some castanets I'd have clicked them in his face.• While drinking our essential morning tea and coffee we were lost in a sea of women in traditional dress with castanets. 