colter vs cutting edge

colter

noun
  • A knife or cutter attached to the beam of a plow to cut the sward, in advance of the plowshare and moldboard. 

  • The part of a seed drill that makes the furrow for the seed. 

cutting edge

noun
  • The sharp edge of the blade of a knife or other cutting tool. 

  • The forefront, or position of greatest advancement in some field. 

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