tumbrel vs tumbril

tumbrel

tumbril

noun
  • A cart used to carry condemned prisoners to their death, especially to the guillotine during the French Revolution. 

  • A cart which opens at the back to release its load. 

  • A kind of medieval torture device, later associated with a cucking stool. 

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