"10 foot" refers to the fact that the GUI's elements—i.e. menus, buttons, text fonts, and so on—are theoretically ergonomically large enough to read easily at a distance of 10 feet (3 meters) from the display (which in this context is normally a large-screen television). To avoid distractions and to be more clear, 10 foot UIs also tend to be very simple and usually only have the minimum core buttons.
Common setting for the 10 foot user interface is a home theater or living room with surround sound speaker setup. The distance between viewer and TV varies, but is typically 10 foot with a 32 inch or larger big-screen television display.
10 foot interfaces are used by devices or software applications dedicated to its user interface being displayed on a television. Television here is defined to be a typical living room television experience, meaning displayed on a big screen, where the user is sitting far away from it, and the dominant form of input will be something like a D-pad on a remote control, (with only up, down, left, and right buttons), not through touch or mouse.
"Ten foot" is used to differentiate the GUI style from those used on desktop computer screens, which typically assume the user's eyes are less than two feet (60 cm) from the display. The 10 foot GUI is almost always designed to be operated by a hand-held remote control. The 10 foot user interface has extra large buttons with menu fonts that are easily read and navigated.
This difference in distance has a huge impact on the interface design compared to typical desktop computer interaction when the user is sitting at a desk with a computer monitor, and using a mouse and keyboard (or perhaps a joystick device for video games) which is sometimes referred to as a "2-foot user interface". Ten-foot interfaces may resemble other post-WIMP systems graphically, due to a similar paucity of pixels, but do not assume the use of a touch screen.
The goal of 10 foot user interface design is to make the user's interaction as simple and efficient as possible, with as few button presses as possible while still having an intuitive layout, in terms of accomplishing user goals—what is often called user-centered design. Good user interface design facilitates finishing the task at hand without drawing unnecessary attention to itself. Graphic design may be utilized to support its usability, however the design process must balance technical functionality and visual elements (e.g., mental model) to create a system that is not only operational but also usable and adaptable to changing user needs.