dynamo vs meteoroid

dynamo

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

  • An electricity generator; a dynamo-electric machine. 

  • An energetic person. 

meteoroid

noun
  • A relatively small (sand- to boulder-sized) fragment of debris in a star system that produces a meteor when it hits the atmosphere 

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