bellwether vs conductor

bellwether

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

  • Anything that indicates future trends. 

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

conductor

noun
  • An ideal of a ring that measures how far it is from being integrally closed 

  • One who conducts or leads; a guide; a director. 

  • A person who conducts an orchestra, choir or other music ensemble; a professional whose occupation is conducting. 

  • A grooved sound or staff used for directing instruments, such as lithontriptic forceps; a director. 

  • A person who takes tickets on public transportation and also helps passengers. 

  • Something that can transmit electricity, heat, light, or sound. 

  • A leader. 

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