contrivance vs dynamo

contrivance

noun
  • A (mechanical) device to perform a certain task. 

  • Something overly artful or artificial. 

  • A means, such as an elaborate plan or strategy, to accomplish a certain objective. 

dynamo

noun
  • An electricity generator; a dynamo-electric machine. 

  • The mechanism by which a celestial body, such as the Earth or a star, generates a magnetic field. 

  • An energetic person. 

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