crotchet vs delirament

crotchet

noun
  • A square bracket. 

  • The arrangement of a body of troops, either forward or rearward, so as to form a line nearly perpendicular to the general line of battle. 

  • A hook-shaped instrument, especially as used in obstetric surgery. 

  • A musical note one beat long in 4/4 time. 

  • An indentation in the glacis of the covered way, at a point where a traverse is placed. 

  • A forked support; a crotch. 

delirament

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