As a Noun: 1. A Spanish musical instrument which consists of two small round pieces of wood or plastic connected by a cord. You hold them in your hand and knock the pieces together to make a noise. English = castanet, castanets. 2. A country in south west Europe, east of Portugal and south of France, called Spain. As a Verb or Adjective: 1. To play castanets. 2. To be someone or something from or relating to Spain. English = (be) Spanish.