cotter vs fibula

cotter

noun
  • A cotter pin. 

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

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

verb
  • To fasten with a cotter. 

fibula

noun
  • An ancient kind of brooch used to hold clothing together, similar in function to the modern safety pin. 

  • The smaller of the two bones in the lower leg. 

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