bellwether vs compendium

bellwether

noun
  • Anything that indicates future trends. 

  • A stock or bond that is widely believed to be an indicator of the overall market's condition. 

  • The leading sheep of a flock, having a bell hung round its neck. 

compendium

noun
  • A collection of board games packaged in a single box. 

  • A short, complete summary; an abstract. 

  • A collected body of information on the standards of strength, purity, and quality of drugs. 

  • A list or collection of various items. 

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