Menu button
From Infogalactic: the planetary knowledge core
This shows the menu button (circled in red in the top image) on the Firefox web browser. When clicked, as shown in the lower image, a pop-out menu container appears.
A menu button is a graphical control element which contains drop down menus. It is a single button, which typically consists of three horizontal bars, and is distinguished from a menu bar in that a menu button does not actually show the menu until someone clicks upon the button, while a menu bar shows the highest-level menu options.
This shows a website menu button on the left (circled in red in the top image) on CNN.COM. When clicked, as shown in the second image, a location choice replaces the page being viewed. The third image shows a menu button circled in red on TVTropes.COM. When it is clicked, a menu pops out on the left and the original page is dimmed.
Menu buttons may appear on application programs, such as the menu button on the far right side of the Firefox web browser, and is commonly used for menu or navigational controls on websites.
