Also from blog.reedsy.com:

With roots in folklore and collections like Grimms' Fairy Tales and Aesop's Fables, (very) short stories have been around for centuries. They fell out of fashion for a while, but recently came back in a big way — not entirely surprising for a generation that publish 140-character 'stories' every day. Depending on who you ask, there are up to six different categories:

1. Flash fiction: Max 1500 words.
2. Sudden fiction: Max 750 words.
3. Drabble, or microfiction: Max 100 words.
4. Dribble, or minisaga: Max 50 words.
5. Twitterature: Max 280 characters.
6. Six-word story: Any story with a single-digit word count is a category unto itself.