Atmosphere:
The emotional mood created by the entirely of a literary work, established partly by the settling and partly by the author's choice of objects that are described. Even such elements as a description of the weather can contribute to the atmosphere. frequently, atmosphere foreshadows events.


Example:
"A throng of bearded men, in sad–coloured garments and grey steeple–crowned hats, inter–mixed with women, some wearing hoods, and others bareheaded, was assembled in front of a wooden edifice, the door of which was heavily timbered with oak, and studded with iron spikes."
-The Scarlet Letter


Explanation:
The beginning of The Scarlet Letter is a great example of atmosphere. Nathaniel Hawthorne describes the people as dark, gloomy, plain people with dark depressing colors on. He then goes on to describe the wooden door with iron spikes. The descriptions of the objects (hats and door) shows that its not a happy place with friendly people.. which can help the reader foreshadow the characters and events that will happen later in the novel. This is exactly what Hawthorne wanted, and that is why he described the atmosphere as early as he possibly could in the novel.