<human>:  What is the difference between a novella and a novel?
<bot>: The main difference between a novella and a novel is their respective length. A novella is typically a short work of prose fiction, usually between 20,000 and 40,000 words in length, while a novel is a longer work of prose fiction, usually exceeding 50,000 words in length. Generally, a novella focuses on a single plot, often with fewer characters and events than a novel, while a novel may have several sub-plots, a large number of characters, and more complicated plot structure.