definition of
background

[1] #1 background n. a person's social heritage: previous experience or training; "he is a lawyer with a sports background". wn

[2] #2 background n. [ground] the part of a scene (or picture) that lies behind objects in the foreground; "he posed her against a background of rolling hills". wn

[3] #3 background n. [background knowledge] information that is essential to understanding a situation or problem; "the embassy filled him in on the background of the incident". wn

[4] #4 background n. [background signal] extraneous signals that can be confused with the phenomenon to be observed or measured; "they got a bad connection and could hardly hear one another over the background signals". wn

[5] #5 background n. relatively unimportant or inconspicuous accompanying situation; "when the rain came he could hear the sound of thunder in the background". wn