1. Background is used to describe processes running on a computer that don't need input from the user.My anti-virus program runs in the background when the processor is idle.
2. The furthest part of an image from the viewer while another object is exist in front of background.You need to set a smaller aperture value to take a photo with a blurred background.
3. Your experience of working or education, criminal history.I have a background in software engineering.He was the prime suspect because of his background.
4. Origin, social heritage.He comes from a working-class (or wealthy) background.