interlock vs tenon

interlock

verb
  • To fit or clasp together securely. 

  • To interlace. 

noun
  • A safety device that prevents activation in unsafe conditions. 

tenon

verb
  • To fit with tenons. 

  • To make into a tenon. 

noun
  • A projecting member left by cutting away the wood around it, and made to insert into a mortise, and in this way secure together the parts of a frame. 

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