fastening vs fibula

fastening

noun
  • A hook or similar restraint used to fasten things together; fastener. 

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 fastening and fibula occurred in a corpus of books? (source: Google Ngram Viewer )