What is the difference between GUI = Graphical User Interface and UI = User Interface?
Nothing - just jargon. GUI = Graphical User Interface, UI = User Interface. You can use them interchangeably.
GUI is "graphical user interface" and UI is just "user interface." GUI is a subset of UI. UI can include non-graphical interfaces such as screen readers or command line interfaces which aren't considered GUI.
A "G".
That "G" stands for "graphic" - not all user interfaces are graphic. Some programs have textual interfaces. Some watch movements of your retinas, or talk to you in audible Chinese, or... or....
There is no major difference(high level) between them but if you want some points to explain the 2 you can refer the below link UI can just be any command line interface or a simple text input/output screen GUI would mean more usser friendly.
An explanation can be as below. "The UI is that part of the machine you use to control the machine and it sometimes has instruments to inform you about the status of the machine. For example an excavator can be controlled by several handles to dig, but could also give information about how many oil is left or at what temperate the engine is running. It is the central point of control and information.
The graphic user interface is where you control the machine in a graphical environment. Usually you control a computer by keyboard and mouse and you see all information on a screen. You see what your input is (what you want to control) and what the output is (the information the computer gives back) all on screen. " The link is below. http://toostep.com/question/what-difference-between-gui-and-ui
there are different types of UI's than just GUI's. GUI usually refers to WIMP style interfaces: windows, icons, menus, pointer. There's also CLI or command line interface, and ZUI or zooming interface, or Touch Screen interfaces, or hardware interfaces (like game controllers) etc... etc...
Keyword - Graphical.
User Interface
In the industrial design field of human-machine interaction, the user interface is (a place) where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the machine which aids the operator in making operational decisions. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls. and process controls. The design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology.
A user interface is the system by which people (users) interact with a machine. The user interface includes hardware (physical) and software (logical) components. User interfaces exist for various systems, and provide a means of:
* Input, allowing the users to manipulate a system, and/or
* Output, allowing the system to indicate the effects of the users' manipulation.
Graphical User Interface
A graphical user interface (GUI) (sometimes pronounced gooey[1]) is a type of user interface item that allows people to interact with programs in more ways than typing such as computers; hand-held devices such as MP3 players, portable media players or gaming devices; household appliances and office equipment with images rather than text commands. A GUI offers graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels or text navigation to fully represent the information and actions available to a user. The actions are usually performed through direct manipulation of the graphical elements.
There are lots of other types of User Interfaces.
See http://en.wikipedia.org/wiki/User_interface#Types
Source - Wikipedia