colter vs rambo

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. 

rambo

noun
  • knife 

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