chainlet vs keyholder

chainlet

noun
  • A small chain. 

keyholder

noun
  • A device or component for holding a key. 

  • The individual or organisation with access to a cryptographic key. 

  • A dominant partner who controls whether their submissive partner is able or allowed to orgasm or receive sexual stimulation, typically by locking the submissive partner in a chastity belt or chastity cage. 

  • One who holds the key to a building etc. for security reasons. 

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