n. [ Back, a. + ground. ] [ 1913 Webster ]

1. Ground in the rear or behind, or in the distance, as opposed to the foreground, or the ground in front. [ 1913 Webster ]

2. (Paint.) The space which is behind and subordinate to a portrait or group of figures. [ 1913 Webster ]

☞ The distance in a picture is usually divided into foreground, middle distance, and background. Fairholt. [ 1913 Webster ]

3. Anything behind, serving as a foil; as, the statue had a background of red hangings. [ 1913 Webster ]

4. A place in obscurity or retirement, or out of sight. [ 1913 Webster ]

I fancy there was a background of grinding and waiting before Miss Torry could produce this highly finished . . . performance. Mrs. Alexander. [ 1913 Webster ]

A husband somewhere in the background. Thackeray. [ 1913 Webster ]

5. 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; as, within the background of the massive budget deficits of the 1980's, new spending programs had little chance of passage by the congress. [ PJC ]

6. 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 }; as, against the background of their expulsion by the Serbs, the desire of Kosovars for vengeance is understandable though regrettable. [ PJC ]

7. (Science) 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. Specifically: (Physics) 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. [ PJC ]

8. (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. [ PJC ]

To place in the background, to make of little consequence.
To keep in the background, to remain unobtrusive, inconspicuous or out of sight; -- of people.
deep background, (Journalism) the status of an interview which must not be quoted in a publication, even without attribution. Compare background{ 8 }. [ 1913 Webster +PJC ]

n. (Computers) The execution of low priority programs while higher priority programs are not using the processing system.
Syn. -- background processing [ WordNet 1.5 ]