The novel is a genre of fiction writing distinguished from the short story, the novella, and drama. The novel has much in common with these other forms of fiction writing, but is distinguished by certain formal traits and, especially, length. 

The central defining trait of the novel as a form is the use of prose.

Prose is the most typical form of language, applying ordinary grammatical structure and natural flow of speech rather than rhythmic structure (as in traditional poetry).

The use of prose and dialogue used to tell a story involving one or more characters (usually more than one) distinguishes the novel from drama and poetry. 

Often the novel is defined simply as an extended narrative, longer than a short story and longer than a novella.

A novel is a book of long narrative in literary prose.

Traditional novels offer a strong plot that poses a problem or set of problems to the characters in the narrative, some of which are resolved in the action of the novel. 

Some novels break with tradition and eschew conventional plot structure, either by telling multiple stories that are interwoven involving characters that are not directly related (A Visit from the Goon Squad; USA), by utilizing a highly imaginative formula of story within story (Naked Lunch), or by including mulitple prose forms within the novel and using these to supplement the narrative (Moby Dick). 

Considering this type of flexibility in the genre, we can see that there is a great deal of variety allowed by the novel form. 

Novel, is a word derived from the French word for new--nouvel is one form of this adjective, which is itself from the Latin.  The novel became a new genre in 1740 when Samuel Richardson published Pamela. 

With the Industrial Revolution there was an expansion of the middle class in England, and since many people then could read and had money to spend on the diversion, the novel came to satisfy their interests in narratives that were imaginary.  Before the novel, people read biographies, autobiographies, journals, and memoirs.  But with the fictionalized novel--a new idea--the narrative could be made exiciting and be controlled by the writer.  Since Alexander Pope's declaraction that "the proper study of mankind is man," authors have been working with the various genres of novels to convey the human experience.

Novels are constructed in a similar fashion to short stories.  That is, they contain a plot with characters, they have settings, theme(s), and point(s) of view. And, they are arranged into genres such as romance, horror, mystery, satire, comedy, historical romance, science-fiction, fantasy, etc.  While there are these many divisions among novels, all have one characteristic:  they have a focus on an inner vision of reality.  In The Rise of the Novel (1957)  by Ian Watts, the author indicates that the "realism of the novel allows a more immediate imitation of individual experience."  Thus, readers find a close correspondence between life and art.