hamburger icon (slide drawer navigation)
A hamburger icon, in user interface (UI) design, is a navigational symbol consisting of three stacked horizontal lines that indicate the location of a hidden menu. The icon got its name from the fact that its structure resembles a burger in a bun in a simplified graphic. When an end user clicks, taps or touches the icon, the menu slides out from the side of the screen, presenting a set of options for future action. The hamburger icon may also be referred to as a menu icon or a slide drawer icon.
Use of a hamburger icon illustrates a principle in user experience (UX) design called progressive disclosure. An important goal of progressive disclosure in website and mobile app design is to free up valuable screen real estate by only showing information that is relevant to the end user's current activity. Additional information and features can be accessed when requested as users move through the website or app.
Norm Cox, a graphic designer at Xerox, created the icon as part of the user interface (UI) for a computer workstation called the Xerox Star. The workstation, which was released in 1981 and promoted as an office automation system, featured a ground-breaking graphical user interface (GUI) that used images of familiar office objects like file folders and trash cans to represent tasks. The desktop metaphor was quickly adopted by other computer vendors and is still in use today.
Although the hamburger icon has been used for decades, its learnability is often a subject of debate between digital user experience professionals. Learnability is a design principle that addresses the ease with which users are able to accomplish basic tasks the first time they encounter a design. Proponents of the hamburger maintain that most end users are familiar with the icon and as computing becomes more mobile, the icon will continue to play an important role in providing a natural user interface, simply because the available screen space on mobile devices is limited. Detractors maintain that navigation options hidden behind a hamburger will most likely be forgotten because the icon must be clicked before any options can been seen. Detractors of sliding drawer navigation and the hamburger icon often prefer a tabbed or tiled approach to navigation.