Novels are typically fictitious prose.
The category of novel, should be reserved for published novels; not webnovels (see Webnovel) or printed novels. This does, however, include e-books with a valid ASIN.
E-Books are books that have been published for a digital platform, such as Kindle.
Light novels are small, Japanese books. They often include some illustrations interspersed between chapters, though they do not have to. These books are generally intended for young adult readers more than adult, and are very popular in Japan.
Light novels have a very "light", easy to read writing style and are intended for entertainment purposes. Paragraphs are short and dialogue abounds in these books, and the pacing tends to be slow. There are often black and white illustrations within light novels.
Webnovels are a serialised form of novel that are posted on sites such as Kakaopage, Joara and Naver. They often do not have official English translations.