Novella
A novella was a short novel or longer short story.
In 1953, after Douglas Pabst rejected Russell's "Deep Space Nine" story, the editor suggested that Benny Russell write a novella based on a picture he handed to him, saying he'd print it in the next month's issue of Incredible Tales and might even get a shot at the cover. Later, Russell presented him with six sequels to the original instead of the novella he asked for. (DS9: "Far Beyond the Stars")