a software interface designed to standardize and simplify the use of computer programs, as by using a mouse to manipulate text and images on a display screen featuring icons, windows, and menus.
British Dictionary definitions for graphical user interfaces
graphical user interface
noun
1.
an interface between a user and a computer system that involves the use of a mouse-controlled screen cursor to select options from menus, make choices with buttons, start programs by clicking icons, etc GUI