The three-dash graphic that is clicked or tapped to display a menu on screen. The analogy is a list, and the metaphor is the three-layer hamburger: bottom bun, meat and top bun. See
ellipsis.
Not Much to Look At
Although a stretch of imagination, the horizontal lines (middle) are the common hamburger icon. The vertical dots (right) are also a menu icon, more accurately defined as an "ellipsis."
A Typical Hamburger Icon
In Windows 10 Tablet mode, a hamburger icon is displayed in the upper left corner of the screen.