What is a work of narrative fiction that is longer than a short story but shorter than a novel called?

A work of narrative fiction that falls between a short story and a novel in terms of length is referred to as a novella. Novellas typically range from about 20,000 to 40,000 words, providing enough space for more developed character arcs and complex plots than a short story, but still remaining concise compared to full-length novels. This distinct category allows for exploration of themes and narratives in a focused yet substantial format, making it ideal for authors who wish to tell a complete story without the extended length of a novel.

In contrast, the other options refer to different forms of writing: an anthology is a collection of various works, usually by multiple authors; serialized fiction is presented in installments, often released over time; and a short story is generally much shorter than a novella, typically under 20,000 words, with a sharper focus on a single theme or event. Each of these forms serves a unique purpose in literature, but the novella stands out for its particular balance between brevity and depth.