ductus vs snorkel

ductus

noun
  • a duct, tube or canal in the body 

  • a subtle reduction of weight towards the middle of the stroke of the letter 

  • the number of strokes that make up a written letter, and the direction, sequence and speed in which they are written (Compare graph; see also aspect.) 

snorkel

noun
  • A hollow tube, held in the mouth, or mounted on and opening into a diving mask, used by swimmers for breathing underwater. 

  • A snorkel parka. 

  • A retractable tube fitted in diesel-engine submarines to allow sufficient ventilation that the engines may be used at periscope depth. 

verb
  • To use a snorkel. 

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