Concept
Constraint
Also: Beschränkung, Randbedingung
Anything that shapes what can happen in a system — rules, habits, physical layout, incentives, relationships. Constraints do not only restrict; they also make things possible.
Constraints are at the heart of how Cynefin explains the domains: ordered systems are held by strong, rigid constraints; complex systems by loose, interacting ones; chaos is the near-absence of effective constraints. Changing constraints is often the most effective way to change a system — far more than prescribing outcomes.
Cynefin distinguishes, among others, governing, enabling and fixed constraints, and treats constructors as their own category.
Further reading: cynefin.io/wiki/Constraints