knock vs trephine

knock

verb
  • To rap one's knuckles against something, especially wood. 

  • To criticize verbally; to denigrate; to undervalue. 

  • To kick a ball towards another player; to pass. 

noun
  • An abrupt rapping sound, as from an impact of a hard object against wood. 

  • A sharp impact. 

  • A batsman's innings. 

  • A blow or setback. 

  • Preignition, a type of abnormal combustion occurring in spark ignition engines caused by self-ignition; also, the characteristic knocking sound associated with it. 

  • Synonym of hunger knock 

  • A criticism. 

trephine

verb
  • To perforate with a trephine. 

  • To use a trephine during surgery. 

noun
  • A surgical instrument with a cylindrical blade used to remove a circular section of tissue, f.e. bone or cornea; a trepan. 

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