Graphical user interface

Abbreviated GUI, pronounced "gooey" A graphics-based user interface that allows users to select files, programs, or commands by pointing to pictorial representations on the screen rather than by typing long, complex commands from a command prompt.

Application programs execute in windows, using a consistent set of pull-down menus, dialogue boxes, and other graphical elements such as scroll bars and icons.  This consistency among interface elements is a major benefit for the user, because as soon as you learn how to use the interface in one program, you can use it in all other programs running in the same environment.