Game Development Dictionary
The program that presents an interface to various operating system functions and services. The name of the shell is derived from the fact that it is an outer layer of interface between users and the inner-workings of the operating systems. Shells are generally classified as either graphical, or command line (text based). As an example, the default shell for Microsoft Windows is called explorer, and some of the functionality it includes is the taskbar and system tray, as well as desktop icons.