bobbin vs trunking

bobbin

noun
  • A spool or cylinder around which wire is coiled. 

  • A fine cord or narrow braid. 

  • The little rounded piece of wood at the end of a latch string, which is pulled to raise the latch. 

  • In a sewing machine, the small spool that holds the lower thread. 

trunking

noun
  • A system of ducts for cables, heating or ventilation. 

  • The movement of containers or packages between a terminal and a transporter's inland facilities, or the scheduled transportation service between locations. 

  • All the electrical and communications cables bundled together and distributed through a building. 

  • Plastic conduit or duct used to conceal and protect electrical wiring. 

  • A two-way radio technique that uses a control channel to automatically assign frequency channels to groups of user radios. 

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