What is a definition of short story?

A short story is fictional work of prose that is shorter in length than a novel. Edgar Allan Poe, in his essay "The Philosophy of Composition," said that a short story should be read in one sitting, anywhere from a half hour to two hours. In contemporary fiction, a short story can range from 1,000 to 20,000 words.
Because of the shorter length, a short story usually focuses on one plot, one main character (with a few additional minor characters), and one central theme, whereas a novel can tackle multiple plots and themes, with a variety of prominent characters. Short stories also lend themselves more to experimentation — that is, using uncommon prose styles or literary devices to tell the story. Such uncommon styles or devices might get tedious, and downright annoying, in a novel, but they may work well in a short story.