halter vs hangman's halter

halter

noun
  • A bitless headpiece of rope or straps, placed on the head of animals such as cattle or horses to lead or tie them. 

  • One who halts or limps; a cripple. 

  • A halter top. 

  • A rope with a noose, for hanging criminals; the gallows rope. 

verb
  • To place a halter on. 

hangman's halter

How often have the words halter and hangman's halter occurred in a corpus of books? (source: Google Ngram Viewer )