A short story is a work of fiction that is usually written in prose, often in narrative format. This format tends to be more pointed than longer works of fiction, such as novellas (in the 20th and 21st century sense) and novels or books. Short story definitions based upon length differ somewhat even among professional writers, due somewhat in part to the fragmentation of the medium into genres. Since the short story format includes a wide range of genres and styles, the actual length is determined by the individual author's preference (or the story's actual needs in terms of creative trajectory or story arc) and the submission guidelines relevant to the story's actual market. Guidelines vary greatly among publishers.

Many short story writers define their work through a combination of creative, personal expression and artistic integrity. As a result, many attempt to resist categorization by genre as well as definition by numbers, finding such approaches limiting and counter-intuitive to artistic form and reasoning. As a result, definitions of the short story based upon length splinter even more when the writing process is taken into consideration.