bones vs castanets

bones

noun
  • A percussive folk musical instrument played as a pair in one hand, often made from bovine ribs. 

  • The act of two fists meeting together in the manner equivalent to a high-five. 

  • The framework or foundation of something. 

castanets

noun
  • A percussion instrument (idiophone) of Spanish origin, consisting of a pair of concave shells joined on one edge by a string, held in the hand and used to produce clicking sounds; any hand-held percussion idiophone that can be played with the fingers, such as bones or spoons. 

How often have the words bones and castanets occurred in a corpus of books? (source: Google Ngram Viewer )