knitting vs switchboard

knitting

noun
  • overhead electrification wires, OHLE 

  • Material that has been, or is being knitted. 

  • The action of the verb to knit; the process of producing knitted material. 

switchboard

noun
  • A large piece of power-distribution equipment that directs electricity to multiple loads. 

  • The electronic panel that is used to direct telephone calls to the desired recipient. 

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