See also: Operating System | Graphical User Interface
Part of the initial OS GUI, the desktop on a computer is designed to look and feel like a real desk surface. Typical desktop objects include icons representing files, buttons, wallpapers, etc.
Desktops usually feature Drag-And-Drop and are easy to use. IRL a tidy desk is a good thing. So a good OS desktop should remain unclutted and be highly customizable.