cam vs centrifugal

cam

noun
  • A spring-loaded camming device, a spring-loaded device for effecting a temporary belay in a rock crevice. 

  • A curved wedge, movable about an axis, used for forcing or clamping two pieces together. 

  • Camera. 

  • A ridge or mound of earth. 

  • A turning or sliding piece which imparts motion to a rod, lever or block brought into sliding or rolling contact with it. 

verb
  • To go on webcam with someone. 

centrifugal

noun
  • A rotating machine used to separate massecuite into sugar crystals and molasses. 

adj
  • Tending, or causing, to recede from the center. 

  • Expanding first at the summit, and later at the base, as a flower cluster. 

  • Having the radicle turned toward the sides of the fruit, as some embryos. 

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