The term widget has been used in the introduction of this section. What exactly is a widget? It's hard to give an exact definition, but `something that can be put on a window' is very close. Some examples of widgets are buttons, scrollbars, labels, listboxes, menu's, checkboxes ... A widgets may or may not accept input from a user; a button certainly does accept input, a label does not, it only shows some information. But all widgets are a part of the entire user interface.