You might call it a 'long narrative fiction'. This term emphasizes the storytelling aspect and the length of the book. Like 'War and Peace' which is a classic example of a long narrative fiction.
A 'saga' is often used to describe a long fictional book. It implies a complex and extensive story. For example, 'The Lord of the Rings' can be considered a saga.
One could say 'epic novel' as another term for a long fictional book.
Novel. For example, 'Pride and Prejudice' is a well - known novel, which is a type of fictional book.
A "fable" can be another word for a fictional story. Fables are short stories that often feature animals as characters and convey a moral lesson.
A long tale. For example, when we talk about a very detailed and extended account of something, we can use 'tale' instead of'story' and 'long tale' to mean a long story.
Tales. Tales can be long or short, but when we talk about long stories, 'tales' can also be used. For instance, 'fairy tales' can be quite long when they are fully developed, with complex plots and multiple characters.
Tale. For example, 'He told a long tale about his adventures.'
Another option is 'protracted story'. It implies that the story goes on for a considerable time. You might also hear 'drawn-out account' used in a similar way.
Well, another word could be 'short novella'. A short novella shares similarities with a long short story in terms of length. It has more room for character development and plot complexity compared to a regular short story, yet it's not as extensive as a full - fledged novel. For example, many classic short novellas manage to tell a rich and engaging story within a relatively concise length.
Epic. An epic is often a long and continuous narrative, usually dealing with heroic deeds and events of great significance.
A 'novella' can also be considered as another word. A novella is shorter than a full - length novel but longer than a short story. It has its own narrative structure and can be as engaging as a novel. So, in some cases, it can be used in place of 'novel book'.