castling vs commutation

castling

noun
  • One that is cast. 

  • A miniature cast or mould. 

  • The act of constructing a defense structure in Japanese chess in which the king (玉) is positioned in a certain way so that it is protected by pawns (歩) and silver general(s) (銀) and/or gold general(s) (金) often with an additional knight (桂) and lance (香車). 

  • A move in which the king moves two squares towards a rook, and the rook moves to the other side of the king; the action of the verb to castle. 

commutation

noun
  • The reversal of an electric current. 

  • The change to a lesser penalty or punishment by the State 

  • Substitution, as a means of discriminating between phonemes. 

  • The process or habit of journeying to and from work on a regular basis; commuting. 

  • Substitution of one thing for another; interchange. 

  • Specifically, the substitution of one kind of payment for another, especially a switch to monetary payment from obligations of labour. 

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