What is "flash fiction"

n. 1 (context countable English) A fictional story that is briefer than typical short story. 2 (context uncountable English) The genre of such stories.

Flash fiction, also called micro fiction, micro narrative, micro-story, postcard fiction, short short, short short story, and sudden fiction, is a style of fictional literature of extreme brevity. There is no widely accepted definition of the length of the category. Some self-described markets for flash fiction impose caps as low as fifty-three words, while others consider stories as long as a thousand words to be flash fiction.