I’ve noticed that some people talk about “fiction novels.”
A novel IS fiction.
One can talk about writing a novel OR about writing fiction. To combine the two is to wear a belt with suspenders. (Another example of reluctance to let the word do the work.)
In writing terms, fiction is any non-factual narrative composition.
It may be short or long.
It may contain historical or scientific facts, and it may describe characters named for historical personages, but the conversations and treatment of events are understood to have been made up by the author.
Fiction may be written in various lengths. Here are some guidelines.
A short story is a fictional narrative of no longer than 20,000 words and no shorter than 1,000. Most short stories run between 3,000 and 10,000 words so that they may be read at a single sitting.
A novelette is a fictional narrative of from 7,500 to 17,500 words in length.
A novella is a fictional narrative between 17,500 and 40,000 words.
A recent fad called “flash fiction” concerns itself with the writing of extremely short narratives. People disagree as to the length of flash fiction. The only point of agreement is that it is shorter than the traditional short story, no longer than 2,000 words. Most flash fiction is between 250 and 1,000 words.
Various terms for these very short narratives are in use. The oldest is “short short story.” More recently one hears “postcard fiction,” “micro-fiction,” “micro-story,” and “sudden fiction.”
Some websites now feature what are called “one sentence stories.” The ones I’ve read don’t appear to be anything more than well-crafted sentences one would expect to find in a conventional story. They tend to be descriptive and anecdotal, but not true stories.
Finally there is the novel, a long fictional narrative that can be from 60,000-100,000 words.
For some authors 100,000 words are not enough:
James Joyce, Ulysses: 250,000 words (It only seems longer.)
Victor Hugo, Les Miserables: 513,000 words.
Leo Tolstoy, War and Peace: 460,000 words in the original; 560,000 words in English translation.
Ayn Rand, Atlas Shrugged: 645,000 words.
Samuel Richardson, Clarissa: 969,000 words. (English majors have to read this early example of an epistolary novel–a story told as a collection of letters.)
AND THE WINNER IS…
Marcel Proust, A la recherche du temps perdu (In English Remembrance of Things Past/In Search of Lost Time): 1.5 million words published in 13 volumes.
NOTE: the above Wikipedia quotation has since been corrected to read “…1.5 million words published in 7 volumes.” Proust was still working on this 7-volume monument when he died. The first English translation, by Scott Moncrief, was published in 12 volumes.