Definition of "Background" :

noun: scenery hung at back of stage

noun: (computer science) the area of the screen in graphical user interfaces against which icons and windows appear

noun: a person's social heritage: previous experience or training

"He is a lawyer with a sports background."

noun: information that is essential to understanding a situation or problem

"The embassy filled him in on the background of the incident."

noun: the part of a scene (or picture) that lies behind objects in the foreground

"He posed her against a background of rolling hills."

noun: relatively unimportant or inconspicuous accompanying situation

"When the rain came he could hear the sound of thunder in the background."

noun: 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."

noun: the state of the environment in which a situation exists

verb: understate the importance or quality of