cotter vs pinball machine

cotter

noun
  • A pin or wedge inserted through a slot to hold machine parts together. 

  • A peasant who performed labour in exchange for the right to live in a cottage. 

  • A cotter pin. 

verb
  • To fasten with a cotter. 

pinball machine

noun
  • A machine specially built to be used to play games of pinball. 

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