What is this type of web control/widget called?

I'm looking to create a menu that is a hybrid of an accordion control and a fly-out menu, but I want to have it expand across the x axis instead of the y:

alt text http://img202.imageshack.us/img202/1185/flyout.jpg

Is there a name for this widget? The name of a jQuery plugin would be even开发者_StackOverflow better.

Thanks

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They're called sidebars. Example: jQuery SideBar.