Flash Fiction is a short story. A very short story. It has a beginning, a middle, and an end, just like a novel would, but it is told in as few words as possible. The definitive number of words has yet to be decided but generally, flash fiction is a story of 1000 words or less.
And in a world where everything is fast, sleep is optional, and books are going out of fashion, flash fiction is easily digestible, a story on one page, on a computer screen with no need to scroll through several hundred pages. Flash fiction is a revolution in story-telling.