airway vs canal

airway

noun
  • A flight path used by aeroplanes. 

  • The trachea. 

canal

noun
  • One of the faint, hazy markings resembling straight lines on early telescopic images of the surface of Mars. 

  • A tubular channel within the body. 

  • An artificial waterway or artificially improved river used for travel, shipping, or irrigation. 

verb
  • To dig an artificial waterway in or to (a place), especially for drainage 

  • To travel along a canal by boat 

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