pendulum vs wristwatch

pendulum

noun
  • A watch's guard-ring by which it is attached to a chain. 

  • Used to refer to the tendency of a situation to oscillate (between two extremes). 

  • A lamp, etc. suspended from a ceiling. 

  • A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity, commonly used to regulate various devices such as clocks. 

wristwatch

noun
  • A watch that is worn on a strap or band fastened around the wrist 

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