Desktop environment
From Knoppix Documentation Wiki
A desktop environment is a complete graphical user interface, (GUI) solution. The desktop environment provides icons, toolbars, applications, applets, and abilities like drag&drop. As a whole, the particularities of design and function of a desktop environment endow it with distinctive look and feel.
The term really only makes sense in the context of systems running the [Xfree86 X Window System]
