In Second Life a great deal of interaction is done through menus. The most common kinds are the drop down menus at the top of the Client Window or in subsidiary windows such as the Inventory Window, pop up menus which are often seen attached to items in the inventory window, and in pie menus which are seen if an inworld object or avatar has a menu associated with them.
Drop Down Menus often have multiple layers indicated by a > which will create hierarchically lower menu, which may in turn have more menus beneath it. The client menus are File, Edit, View, World, Tools, Help, Client and Server. These last two are called the Debug Menus and are not visible by default. They are shown by pressing ctrl-alt-shift-D on the PC, or cmd-opt-shift-D on the Mac OS.
Pie Menus are used more extensively in Second Life than in most other GUIs. Pie Menus are often used to interact with objects that are present inworld. They can have layers which are seen by selecting the "More" option at the bottom of a pie menu. (See Avatar Menu, Object Menu).