bijou vs keychain

bijou

noun
  • A piece of jewelry; a trinket. 

  • A jewel. 

  • A small intricate piece of metalwork. 

adj
  • small, little (often implying affection) 

  • intricate; finely made 

  • small and elegant 

keychain

noun
  • An ornamental piece holding such a chain or ring. 

  • A chain or ring to which a key may be attached. 

  • A digital repository for the storage of cryptographic keys. 

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