cutting edge vs toenail

cutting edge

noun
  • The sharp edge of the blade of a knife or other cutting tool. 

  • The forefront, or position of greatest advancement in some field. 

toenail

noun
  • The thin, horny, transparent plate covering the upper surface of the end of a toe. 

verb
  • To fasten two pieces of lumber together by applying nails or screws into both boards at an angle. 

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