cotter vs treenail

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. 

treenail

noun
  • A wooden peg or pin used as a fastener. 

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