eponym vs screen name

eponym

noun
  • A real or fictitious person's name that has given rise to the name of a particular item. 

  • A word formed from a real or fictive person’s name. 

  • A word formed from a real or fictive place or thing. 

screen name

noun
  • a pseudonym used for Internet communications 

  • Synonym of stage name 

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