A short story has no set definition, except that it is a narrative and is shorter than a novel. According to Writing-World.com, a short story is between 1,000 and 7,500 words, though other sources suggest it is between 1,000 and 17,000 words, or even up to 30,000 words.
In his essay "The Philosophy of Composition," Edgar Allan Poe claimed short stories should be short enough to be read in one sitting, meaning anywhere from half an hour to two hours. Although reading speeds vary greatly among people, this has been interpreted to mean between 1,000 and 20,000 words.
Due to the abbreviated length of short stories, they generally only have one main character and one central plot, as opposed to the many characters and complex plots some novels have. Although that may suggest the short story is a limiting medium, the shorter length allows for more experimentation. A writing style or trope can be used and tested in a short story, where the reader only spends a short time with it, as opposed to a novel where it may become tedious and annoying. Stories shorter than 1,000 words are termed flash fiction, and stories too long to be a short story but not quite the length of a novel (estimated at a minimum of 50,000 words) are called novellas.