fiction vs novella

fiction

noun
  • A legal fiction. 

  • Literary type using invented or imaginative writing, instead of real facts, usually written as prose. 

  • A verbal or written account that is not based on actual events (often intended to mislead). 

novella

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

  • A short novel or long short story. 

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