Mood is a literary device authors use to evoke feelings within their readers. They create mood with their setting and character descriptions, tone and diction, or word choice.
Mood and tone are commonly confused literary terms. Mood typically refers to the atmosphere created within the story, while tone is the author's attitude toward the subject. The emotional atmosphere of a literary work such as a novel creates the major impression on the reader, which is the mood of the piece. It may have nothing to do with the author's personal feelings on the topic, which is the tone.
One way an author creates a mood is through word choice. Positive mood words include optimistic, content, passionate, thankful and giddy. Negative mood words include discontented, predatory, restless, morose and merciless. Writers use such words to describe a situation, setting or character, thus evoking a feeling in the reader.
The setting of a story is the time and place of the action. One literary example of using descriptive setting words to create a mood comes from Charles Dickens' "Pickwick Papers." Dickens describes the sky as clear blue and a river as glistening and sparkling. According to Literary Devices, such word choice makes readers feel the serenity of the scene.
Authors also use tone to create the mood. For instance, in Robert Frost's "The Road Not Taken," Frost describes sighing while making his decision. This unhappy tone creates a regretful mood in the poem.