A novel is loosely a long fiction prose involving character and action and telling a story. The novel is longer (at least 50,000 words) and more complex than either the short story or the novella.
Description is not so much an element of fiction as its very essence; it is the creation of mental images that allow readers to fully experience a story. When you write a story, you offer an account of a chain of events, the characters that inhabit those events, and the places in which those events occur. How you describe those events, characters, and places affects your readers' perceptions. - Description by Monica Wood
Good writers may "tell" about almost anything in fiction except the characters' feelings. One may tell the reader that the character went to a private school (one need not show a scene at the private school if the scene has no importance for the rest of the narrative), or one may tell the reader that the character hates spaghetti; but with rare exceptions the characters' feelings must be demonstrated: fear, love, excitement, doubt, embarrassment, despair become real only when they take the form of events--action (or gesture), dialogue, or physical reaction to setting. Detail is the lifeblood of fiction. - On Becoming a Novelist by John Gardner