duct vs water pipe

duct

noun
  • a pipe, tube or canal which carries gas or liquid from one place to another 

  • a vessel for conveying lymph or glandular secretions such as tears or bile 

  • a tube or elongated cavity (such as a xylem vessel) for conveying water, sap, or air 

  • a layer (as in the atmosphere or the ocean) which occurs under usually abnormal conditions and in which radio or sound waves are confined to a restricted path 

  • an enclosure or channel for electrical cable runs, telephone cables, or other conductors 

verb
  • to enclose in a duct 

  • to channel something (such as a gas) or propagate something (such as radio waves) through a duct or series of ducts 

water pipe

noun
  • A pipe that is a conduit for water; an essential element of plumbing. 

  • A device for smoking, such as a hookah or bong, in which the smoke is drawn through a container of water before inhaling. 

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