Menus are composed of three hierarchical pieces. The menu bar contains the various menus. The menu bar is at the top of the screen on a Macintosh and in the top of the window in Windows and Motif.
Each menu bar contains one or more menus. Menus are organized topically. File would be one menu. Edit would be another.
Each menu contains one or more menu items. The menu items are the individual actions such as Open, Print, Cut or Copy. They are not shown except when the menu is active. No more than one menu will be active at a time.
This Edit menu has a disabled Undo menu item followed by a separator, followed by enabled Cut, Copy, paste and Clear menu items, followed by another separator, followed by an enabled Select All menu item.