byname vs nom de clavier

byname

noun
  • A pseudonym; nom-de-plume. 

  • A ritual title for a god or goddess used in Heathenry. 

nom de clavier

noun
  • A pseudonym used in online communications; a handle. 

How often have the words byname and nom de clavier occurred in a corpus of books? (source: Google Ngram Viewer )