In User Interface frameworks, a composite control is a control _composed_ of other existing child controls.
In User Interface frameworks, a composite control is a control composed of other existing child controls (a control being a UI element that the user can interact with such as a slider or a button).
The idea is create a custom control without having to develop the rendering of the control: it is delegated to the child controls. A composite control can itself be re-used as a child control of a higher composite control, thus making a hierarchy of controls.
.NET reference documentation about composite controls: http://msdn.microsoft.com/en-us/library/aa719968(v=vs.71).aspx
