background

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The ground or scenery located behind something.
2. n. The part of a pictorial representation that appears to be in the distance and that provides relief for the principal objects in the foreground.
3. n. The general scene or surface against which designs, patterns, or figures are represented or viewed.
4. n. A position or area of relative inconspicuousness or unimportance.
5. n. The circumstances and events surrounding or leading up to an event or occurrence.
6. n. A person's experience, training, and education: Her background in the arts is impressive.
7. n. Subdued music played especially as an accompaniment to dialogue in a dramatic performance.
8. n. Sound that intrudes on or interferes with an audio recording.
9. n. Low-level radiation, as from radioactive decay, that exists as part of the natural environment.
10. idiom. on background For publication but without specific attribution of the source: The Senator would only speak on background with the reporter about the crisis.
11. idiom. on deep background For publication without any attribution of the source.

Century Dictionary and Cyclopedia

1. n. The ground at the back or behind, as opposed to the front; situation in the rear of those objects, considerations, etc., which engage the attention; subordinate or secondary position in contradistinction to principal or important position; place out of sight: used both literally (of physical objects) and figuratively: as, there were mountains in the background; the true reasons for this action were kept in the background.
2. n. Specifically The part of a picture represented as furthest from the spectator's eye: opposed to foreground. In pictures of which the foreground possesses the chief interest, the background is so designed as to enhance the effect of objects in the foreground, to which it is kept subordinate in color, etc., often serving no other purpose than that of a mere screen or setting behind the objects in which the interest is concentrated: as, a portrait with a landscape background; a group of figures with buildings in the background. In landscapes, when no such evident opposition is intended, or when the chief interest lies in the background, the term distance is properly used to denote the more distant planes in the picture, as distinguished from the foreground and the middle distance.
3. n. In photography, the plain or decorated screens, properties, etc., placed behind the subject in taking portraits, especially in regular gallery-work, in order to form an appropriate setting in the finished picture.

Wiktionary

1. n. One's social heritage; what one did in the past/previously.
2. n. A part of the picture that depicts scenery to the rear or behind the main subject; context.
3. n. Information relevant to the current situation about past events; history.
4. n. A less important feature of scenery (as opposed to foreground.)
5. n. computing The image or color, over which a computer's desktop items are show (e.g. icons or application windows).
6. n. computing Activity on a computer that is not normally visible to the user
7. v. To put in a position that is not prominent

GNU Webster's 1913

1. n. Ground in the rear or behind, or in the distance, as opposed to the foreground, or the ground in front.
2. n. (Paint.) The space which is behind and subordinate to a portrait or group of figures.
3. n. Anything behind, serving as a foil.
4. n. A place in obscurity or retirement, or out of sight.
5. n. The set of conditions within which an action takes place, including the social and physical conditions as well as the psychological states of the participants.
6. n. The set of conditions that precede and affect an action, such as the social and historical precedents for the event, as well as the general background{5}.
7. n. (Science), (Physics) The signals that may be detected by a measurement which are not due to the phenomenon being studied, and tend to make the measurement uncertain to a greater or lesser degree. Electronic noise present in a system using electronic measuring instrument or in a telecommunications system, which may hide and which must be differentiated from the desired signal; also called background noise or noise.
8. n. (Journalism) An agreement between a journalist and an interviewee that the name of the interviewee will not be quoted in any publication, although the substance of the remarks may be reported; -- often used in the phrase “on background”. Compare deep background.

WordNet 3.0

1. n. the state of the environment in which a situation exists
2. n. relatively unimportant or inconspicuous accompanying situation
3. n. extraneous signals that can be confused with the phenomenon to be observed or measured
4. v. understate the importance or quality of
5. n. information that is essential to understanding a situation or problem
6. n. the part of a scene (or picture) that lies behind objects in the foreground
7. n. a person's social heritage: previous experience or training
8. n. scenery hung at back of stage
9. n. (computer science) the area of the screen in graphical user interfaces against which icons and windows appear