There are meta-systems and super-systems. What is the difference between them ? Super-system is a system containing the current system. But meta-system is a system that studies it.
There are different types of study. Collecting information about a system is one type of study. It may include sensing the parameters of a system. According to TRIZ sensing and studying is always eventually complemented by controlling. Thus, a system that senses parameters of another system and controls it based on the information collected, is its meta-system. In other words, the controller is a primitive meta-system of a system that it controls. This coincides with definition of meta-system in cybernetics.
But TRIZ goes beyond cybernetics. There are more sophisticated types of study than just primitive collecting/sensing information. They, for instance, involve discovering the laws that govern systems. That is why Control Theory is a meta-system of all control-systems/controllers. Although a controller that controls another controller is also its meta-system, the Control Theory is their common meta-system of a higher order. It studies systems at a qualitatively higher level than controllers do, which simply collect information. It presents theory of controllers.
Thus, from the standpoint of TRIZ, theory of any system is also its meta-system. Mechanical engineering is a meta-system of all mechanical systems. And TRIZ is a meta-system of the art of inventing !
This issue is devoted to other meta-systems.