hamburger icon

The  hamburger icon  is a triple bar symbol commonly used to indicate a hidden navigation menu. Google has referred to this icon as "hotdog."  It was first used on the Xerox Star in the early 1980s

Articles

 * 2015-05-16 BBC News: Hamburger icon: How these three lines mystify most people
 * 2014-10-29 Antonio/Placeit Blog A Brief History of the Hamburger Icon