comet vs meteoroid

comet

noun
  • A small Solar System body consisting mainly of volatile ice, dust and particles of rock whose very eccentric solar orbit periodically brings it close enough to the Sun that the ice vaporises to form an atmosphere, or coma, which may be blown by the solar wind to produce a visible tail. 

  • Any of several species of hummingbird found in the Andes. 

  • A celestial phenomenon with the appearance of such a body. 

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 comet and meteoroid occurred in a corpus of books? (source: Google Ngram Viewer )