A menu presents a set of button-like menu entries to users. A menu entry is not a full fledged Tk widget. Instead, you create a menu widget and then add entries to the menu as shown in the following examples. There are several kinds of menu entries:
Command entries are like buttons.
Check entries are like checkbuttons.
Radio entries are like radiobuttons.
Separator entries are used to visually set apart entries.
Cascade entries are used to post submenus.
Tear-off entries are used to detach a menu from its menu button so that it becomes a new top-level window.
A menubutton is a special kind of button that posts (i.e., displays) a menu when you press it. If you click on a menubutton, then the menu is posted and remains posted until ...