novella vs work of fiction

novella

noun
  • A short novel or long short story. 

  • Synonym of novel (“new legal constitution in Ancient Rome”) 

work of fiction

noun
  • A fictional account; a story. 

  • A fictitious account; an account of events that never took place. 

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