Does anyone know a good synonym for 'GUI' that non-technical people will understand? Or a simple sentence explaining it that still won't scare them off?
I mean this in the context of, for example, letting the user choose between an "Simple GUI" and "Advanced GUI" setting.
What about "the visual part of the application, i.e. its buttons, text boxes and other visual elements"?
In a more detailed form, you would also include that it handles:
The process of displaying the elements to the user through a screen,
The interaction of the user with those elements (most commonly known as events, but it's not limited to events).
Note that non-technical people understand quite well what interface is. This makes it pretty easy to understand what is user interface. The most difficult part is the "G": most non-technical would assume that GUI is the only user interface which exists, and console-style interface is not an interface at all.
There is little need even to explain the idea of interface to users of the program. To them, the program is the interface.
Don't say "the GUI of the program does X". Just say "the program does X".
Don't say "the GUI has a red self-destruct button". Say "the program has a red self-destruct button".
To you, the programmer, it is very important to think about what is part of the GUI and what is not. However, the user couldn't care less about that. The interface, by definition, is the only part they see. The rest is hidden by design.
The only case when the idea of "GUI" might matter to the user is if you have more than one interface. For example, if you have both a command-line and a graphical interface, you may have to distinguish the two in some contexts.
Still, unless your program is closely tied to the command line, you should probably still not say anything about interfaces in any general documentation or information: just talk about the GUI as "the program" in any generic setting, and put the command line options in the documentation (users who want that will know how to find it--and in that part of the documentation you can probably talk about GUIs without fear of people not knowing what it is).
I've always just used the term "screen" instead of GUI, as in: "Would you like the program to show you the simple screen, or the advanced screen?"
You could use "screen layout" as the synonym for Graphical User Interface (GUI). This is easier to understand than the acronym GUI for non technical people. Another alternative would be to spell out the acronym in full wording, and you wouldn´t need a synonym.
If you want to separate the program from the GUI, then you can use 'Basic interface' vs 'Advanced interface'.
If you merge the concerns (program & interface) then you can do what the calculator application on mac and windows does, have multiple views, 'basic', 'advanced' and more if need be. You can also link it with functionality and say, 'basic functionality' or 'advanced functionality'
When Microsoft bolted a GUI on top of DOS, it's possible that someone on the team point proposed calling it "Microsoft GUI for DOS", but in the end they came up with "Microsoft Windows".
A program's GUI in a windowed environment is exactly that: it consists of the set of its windows. (A generality, with possible exceptions like background programs that have a graphical presence in the form of some icon with a context menu.)
Embedded systems which have graphical (or textual) interfaces without windows, where the pages of the UI occupies a full screen, have screens. For example: This rackmount synthesizer's screens are quite intuitive, making it easy to program. Or: Press the Fax button on the copier's main screen to bring up the Fax screen.
The explanatory help text for newbies that you are looking for might be something like:
GUI stands for Graphical User Interface. It is a visual way of interacting with a computer program by manipulating controls which are represented as diagrams on the screen, and by entering any necessary numbers or text into designated boxes, in any order.
GUIs can be complicated, showing many controls at the same time, including rare features used by experts. A complex GUI overwhelms casual users of a program, or beginners. This program accommodates such users by supporting a mode of operation whereby it presents a simplified form of its GUI that is easier to understand and use for common operations. You can switch to the advanced GUI at any time if you aren't able to find a way to do something using the simple GUI.
"The application's face that you interact with, you can see it, you can transmit informations to it, but it's just the part you see, not the clever part of it, not its brain".
