plumbing vs trunking

plumbing

noun
  • The pipes, together with the joints, tanks, stopcocks, taps, and other fixtures of a water, gas, or sewage system in a house or other building. 

  • A system of vessels or ducts in the human body, especially the genitourinary system. 

  • The trade or occupation of a plumber. 

  • Practical, concrete work serving to support other work. 

  • A Murasugi sum where each disk summed along has its boundary subdivided into four segments. 

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 plumbing and trunking occurred in a corpus of books? (source: Google Ngram Viewer )