knock out vs pitchfork

knock out

verb
  • To strike or bump (someone or something) out. 

  • To fall asleep, especially suddenly. 

  • To lose the scent of hounds in fox-hunting. 

  • To eliminate from a contest or similar. 

  • To put to sleep. 

  • To complete, especially in haste; knock off. 

  • To render unconscious, as by a blow to the head. 

  • To exhaust. 

  • To cause a mechanism to become non-functional by damaging or destroying it. 

  • To communicate (a message) by knocking. 

pitchfork

verb
  • To throw suddenly. 

  • To toss or carry with a pitchfork. 

noun
  • An agricultural tool comprising a fork with sparse, light tines, attached to a long handle, used for pitching hay (especially loose hay) high up onto a stack (as on a wagon or haystack, or into a haymow). 

  • A similar fork with slightly more and heavier tines, used for mucking stalls and pitching soiled bedding into a wagon or manure spreader. 

  • Any fork used for farm labor, even a digging fork (but such usage is often considered ignorant by experienced farmers). 

  • A tuning fork. 

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