Definition - What does Wallpaper mean?
Wallpaper, in the context of computing, refers to the image behind the area where menus, icons and shortcuts are displayed. Wallpaper is usually in either a .jpeg or .gif file format and is customizable in most operating systems (OSs).
Wallpaper is also known as the desktop, desktop picture or desktop background.
Techopedia explains Wallpaper
Wallpaper is simply an image that is used as the desktop background. It may be displayed as one image, one stretched image, one image centered on the desktop and surrounded by a solid color or one repeated tiled image that covers the entire desktop vertically and horizontally.
When using Android’s OS on a mobile device, live wallpaper behaves as an application providing the desktop background image, while also providing touch screen user-interaction that allows access to other applications and connected hardware.