So according to one source, the major forms of literary fiction tend to fall into one of three overall categories:
Other sources set the overall umbrella a little differently to include:
Some lists include novel, novella and short story as a subset of Prose. Another list also includes Flash Fiction, Novelette and Epic as subsets of prose in addition to the previous three. So, what is a writer to take away from all of this? Well, I think if you ask more than one person you’ll probably get more than one answer. Just try searching via your favorite search engine to see the results that your search yields. I’ll even wager that if you use different search engines you’ll get a wider and varying range of answers.
I think a compelling reason for defining form in the first place stems from when books were primarily available in print. Think about it – print costs determined not only how much to charge for a book but was also done in an effort to manage reader expectations. With eBooks it’s still an issue of managing reader expectations because if a reader knows that they’re starting a novella, which is typically defined as 17,500 to 50,000 words or 60-170 pages, they expect a different reading experience than say a novel which is over 50,000 words and typically ranges from 170 pages on up. An epic work is over 680 pages!
I would also argue that longer books still tend to be priced higher even when they are in electronic format because they tend to have higher investment costs even if they aren't actually printed on paper.
Of course, with printed books the reader can see immediately how “big” or “small” the book is whereas with eBooks you do have to pay attention to the specifications listed for the book, typically at an online vendor's site.
According to one Wikipedia entry (https://en.wikipedia.org/wiki/Fiction) the following is a breakdown of word and page count for some of the prose categories listed above:
Flash Fiction = less than 2,000 words or approximately 5 pages
Short Story = 2,000 – 7,500 words or 5-25 pages
Novelette = 7,500 – 17,500 words or 25-60 pages
Novella = 17,500 – 50,000 words or 60-170 pages
Novel = 50,000 words or more or about 170 pages
Epic = 200,000 words or more or 680+ pages