cleft vs scarification

cleft

noun
  • A disease of horses; a crack on the band of the pastern. 

  • An opening, fissure, or V-shaped indentation made by or as if by splitting. 

  • A piece made by splitting. 

verb
  • To syntactically separate a prominent constituent from the rest of the clause that concerns it, such as threat in "The threat which I saw but which he didn't see, was his downfall." 

adj
  • split, divided, or partially divided into two. 

scarification

noun
  • A medieval form of penance in which the skin was damaged with a knife or hot iron. 

  • The act of scarifying: raking the ground harshly to remove weeds, etc. 

  • A route of administration for some vaccinations and tests: rather than hypodermic injection, the site is inoculated intradermally not with any injection but rather only with small, shallow pricks or scratches; the needle is not hollow. 

  • The scratching, etching, burning / branding, or superficially cutting designs, pictures, or words into the skin as a permanent body modification. 

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