Back"ground` (&?;), n. [Back, a. + ground.]

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

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

&fist; The distance in a picture is usually divided into foreground, middle distance, and background. Fairholt.

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

4. A place in obscurity or retirement, or out of sight.

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

A husband somewhere in the background.
Thackeray.

• One's social heritage; what one did in the past/previously.
       The lawyer had a background in computer science.
  
• A part of the picture that depicts scenery to the rear or behind the main subject.
  
• Information relevant to the current situation about past events; history.
  
• A less important feature of scenery (as opposed to foreground)
       There was tons of noise in the background.
       The photographer let us pick a background for the portrait.
  
• (computing): (Windows): The solid color that provides contrast with items (usually icons) appearing on it.
  
• (computing): Activity on a computer that is not normally visible to the user
       The antivirus program is running in the background.