Example: "The Apple iPhone has a touchscreen user interface."
A user interface is the means in which a user controls a software program or hardware device. For example, a software interface may include windows, icons, menus, and buttons that allow the user to interact with the program. This is also known as a graphical user interface, or GUI. A hardware interface can be a remote control or a video game controller. It may also refer to the controls on a camcorder, digital camera, or iPod. Most modern user interfaces today are designed using a combination of hardware and software.