Background, setting, environment, milieu, mise-en-scène, backdrop are comparable when they refer to persons and their actions as found in real life or as represented in art and denote the place, time, circumstances, and conditions in which those persons live or carry on their activities. However they vary widely in their derivations and are not always interchangeable.
Background refers primarily to a dramatic performance and to the back and usually dimly lighted part of the stage as distinguished from the betterlighted foreground where the main action usually takes place; it may be used similarly of pictorial art to denote that part of a picture which seems most remote from the spectator and against which the figures or principal objects represented seem to be projected.
In its common extended use the term is often widened in scope to include the whole aspect of the environment of something (as an historical event, a movement, a career, or a phase of a person's or a people's development) that is capable of being seen in perspective and that may be viewed as antecedent, causal, or intimately related to the fundamental quality of what it environs.
Setting also derives its basic implications from the arts, originally from the jewelers' art, where the term is used of the framework of precious metal in which a gem is mounted, and later from the dramaturgists' art, where it is used of the framework (as scenic paintings and furniture) which indicates to the spectator the surroundings in which the action of a play takes place.
Hence setting is preferred to background as a designation of the element in a novel, a play, or other literary representation of human life which is distinguished from the plot and the characters and which is the author's imaginative reconstruction of the time, place, and conditions in which his characters live and act.
When used in reference to real life, setting commonly connotes the standpoint of one who looks at human beings and their activities as though they were dramatic or literary representations.
Environment basically denotes the surroundings and especially the natural surroundings (as of a town, a body of water, or an individual).
When relating to a person or a living being environment commonly suggests not only natural surroundings but any or all external factors (as social or economic conditions, nutrient supply, or crowding) that are important in the physical, mental, and moral development of the species or the individual or as formative influences.
When the formative influences in a person's development are the result of heredity or nature, background is the preferred term; when they are the product of his surroundings or his nurture, environment is the more likely choice; thus, one may say that, although it is impossible to change a child's background, he may turn out well if brought up in a different environment.
Milieu carries none of the scientific implications of environment, yet it also means surroundings and is used chiefly in reference to the physical and social surroundings of a person or group of persons. It is preferred to environment when there is the intent to evoke a clear picture or to suggest the specific character or atmosphere of such surroundings; it may be used in reference to imagined as well as to actual persons and therefore is often interchangeable with setting.
Mise-en-scène is the equivalent of setting, especially as referred to a theatrical performance. However its stronger suggestion of the use of properties to achieve a given atmosphere or theatrical effect is the reason for its preference by some writers when the reference is not specifically to a dramatic performance or even to invented scenes.
Backdrop denotes a drop curtain at the rear of the stage which provides the decorative or realistic background for the action of a play and brings players and their movements into relief; it is increasingly common in an extended sense as a substitute for background or setting or milieu when there is the intent to stress pictorial effect rather than social influence or spiritual significance.