Depends on the publisher, but typically up to 7500 words is a short story, 7500-40,000 is a novella, anything over is a novel. Some have different categories like I think I've heard "novelette" for 7.5k-15k? But that's not universal.

It's for subscribers on www.gregstolze.com so it doesn't really matter. Maybe I'll call it a novelettino.

If Steven King can stick four of them together and make a book it’s a novella.