Graphical User Interface: interface between an operating system or program and the user; it uses graphics or icons to represent functions or files and allow the software to be controlled more easily; system commands do not have to be typed in; GUIs normally use a combination of windows, icons and a mouse to control the operating system.

(Collin, S.M.H. [ed.], Dictionary of Multimedia, Peter Collin Publishing, Teddington, Middlesex, 1995, p117)