Software is classified depending upon its menus option. Menus are the like abilities of the software. It comprises of several tools and commands options these are functions which can be performed using that particular software.
Menus in terms of Maya are unique because in Maya there are sets of different menus pertaining to different types of operations to be performed in Maya. For a particular operation on your Graphics in Maya you have to change the user interface for that. That means you have to choose a set of menus. For an instant you are working in Maya and you choose Animations Menus then the Animation Menu set will be open. And all the functions which are related to Animation can be performed opening the respective tool or command. There are names of some very important set of menus in Maya, Animation menus set, polygon, surfaces, Dynamics, nDynamics , Rendering, Fur, Hair and Cloth menus set. There are some new sets of menus in Maya 2009 which are included in the above list.