billfold vs wallet

billfold

noun
  • A small, folding sleeve or case designed to hold paper currency, as well as credit cards, pictures, etc. 

wallet

noun
  • A small case, often flat and often made of leather, for keeping money (especially paper money), credit cards, etc. 

  • A person's bank account or assets. 

  • An e-wallet or digital wallet. 

  • A thick case or folder with plastic sleeves in which compact discs may be stored. 

  • A person's buttocks (the area of the body nearest where one keeps one's wallet). 

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