A shortcut key on PC keyboards that is used to launch the context sensitive menu in Windows. It is located on the right side of the space bar. Also called the "Context Menu" key, it performs the same operation as right clicking the mouse, which is often done to retrieve the Properties dialog box. See Windows key and Win Properties.

If There Is No Mouse
The Menu key is helpful when there is no mouse connected. If there is one, you might as well right click the item you want because the Menu key only works on the item in focus, which occurs when you click the item in the first place.