A toolbar is a menu of options and functions located on a program window, typically found below the title bar and menu bar. Toolbars have functionality unique to the program they are found in. Early on in computer development, this bar was called the "ribbon," similar to a typewriter ribbon.
Toolbars can be found on anything from image manipulation programs to browsers and all kinds of standard computer applications. Some toolbars allow for adjustment or personalization, letting the user move them about on the window. Some applications can have new toolbars added by downloading extensions that add them, usually from the program's supporting website or a third-party database.