dynamo vs rubber band

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. 

rubber band

noun
  • An elastic band made of rubber. 

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