Novels are long, usually with multiple chapters. Short stories are just that--short. They can be anywhere from 54 words, to 20 pages, to longer, but a novel is significantly longer.
Novels, because they are longer, have the time to create more characters, multiple important events, and to go into more in-depth characterization. Short stories are usually more focused, centering on one major conflict, or relaying a large amount of time in a more distant and summarized manner.
It is extremely hard to define a novel. Perhaps impossible. Once an authority had offered a definition, some writer would be sure to come out with a novel that contradicted it. Henry James once said:
The only thing we should require of a novel is that it be interesting.
It is fairly easy to define a short story. So a novel would be a long story, a story that isn't a short story. Here is a good definition of the modern short story based largely on the dictum of Edgar Allan Poe, who is often described as the "father of the modern short story," or in some such words:
A short story is a dramatic narrative intended to be read in a single sitting and designed to produce a single effect.
A novel is not necessarily intended to be read in a single sitting or necessarily designed to produce a single effect, although some novels can be read in a single sitting. Poe meant by "single sitting" not much longer than an hour. He didn't believe that most readers could retain the same degree of interest and involvement for much more than an hour. In college we see that lectures are usually only about fifty minutes long. If the lecturer goes on much longer, we hear binders clicking and see all kinds of restlessness in the classroom. People can only absorb so much. They start thinking of other things. They have to go to the bathroom or smoke a cigarette or meet a friend--or something.
Short stories are intended to be read in a single sitting in order for the author to produce the intended single effect. We often get interrupted while reading a story, and then we will probably not experience the single effect, unless perhaps we start reading the story all over again. For example, we might start reading a short story in The New Yorker in a waiting room--and then the nurse comes out and says, "The doctor will see you now." Even if we swipe the copy of The New Yorker, we won't get that single effect if we were interrupted part way through.
The single effect (which might be called the single emotional effect, or "feeling") is the most important part of the definition of the modern short story--and it comes directly from the great Edgar Allan Poe. Some of his own short stories serve as good examples of the single effect he was talking about. These stories include "The Cask of Amontillado," "The Tell-Tale Heart," and "The Black Cat." A good way to write about a short story is to analyze the single effect it had on you. Shirley Jackson's famous story "The Lottery" is an excellent example of a short story with a memorable single effect.
The difference between a novel and a short story has to do with length. A short story is obviously shorter in length, but it also may begin later in the plot triangle. Because a novel has more time for development and characterization, the exposition (or introduction ) phase may be much longer than in a short story where it may even be skipped all together. Occasionally, a short story will skip the exposition and catalyst phases entirely and begin during the rising action phase.
A novel will often follow one character's journey. Other novels have intersecting stories, such as Colum McCann's "Let the Great World Spin", or Amy Tan's "Joy Luck Club". The novel uses length to develop its landscapes, plots and characters. Good examples of this method is the historical novel where a specific period in history is examined in great detail. A strong example of this is Hilary Mantel's "Wolf House" which follows the lives of Cardinal Wolsey and Thomas Cromwell in great detail. It would be difficult to condense all that information into a short story!
A short story takes a "slice" of life and focuses on, for example, a single incident, an aspect of love, a specific decision. Where a novel might be 300 pages, a short story will be anywhere from 5-30 pages. The main focus of a short story is to present the reader with a single clarifying moment. An excellent example of this is "Love is Not a Pie" by Amy Bloom that begins with a funeral and ends with an understanding of the mother's live and loves.
Short stories focus upon one or two important events to drive their plot. Novels, on the other hand, may have many different sub-plots, twists, and turns to reach the climax and resolution of the story.
Short stories, as their name denotes, are shorter in nature than full-length books or novels. A novel may be several thousand pages, if warranted, whereas a short story is often measured by its word count.
Editors, in particular, if they are seeking a short story will set a limit of 5,000-15,000 words at the outmost. Novels, with their numerous pages, chapters, and events, can number into the millions for word count, if such length is warranted.
The length is the biggest difference! In a novel, the author is able to give you an in depth look at what the characters are like and how they feel and how they affect others in the story. The setting and the plot are much more explicit. There is much more detail in a novel that there is a short story. A short story is just a glimpse. In "Exploring the Titanic," a non-fiction short story by Robert Ballard, the action is selective. We are only introduced to some of the characters and detail of the story, as to compared to the myriad of novels that have been printed about the tragedy.
A short story is a short invented prose narrative usually dealing with a few characters and aiming at unity effect. Novel is a long invented prose narrative dealing with human experience through a connected sequence of events.
a novel is far much longer than a SHORT-story and the plot is much more developed