The article overviews and elaborates the concept of polycentricity, defined as a structural feature of social systems of many decision centers having limited and autonomous prerogatives and operating under an overarching set of rules. The article starts by introducing the concept as it was advanced by Michael Polanyi and developed by Elinor and Vincent Ostrom. It continues introducing possible instances of polycentricity as well as related notions, as part of an attempt to further elaborate the concept through a concept design approach that systematically applies the logic of necessary and sufficient conditions. The article concludes by arguing that the polycentricity conceptual framework is not only a robust analytical structure for the study of complex social phenomena, but is also a challenging method of drawing non-ad hoc analogies between different types of self-organizing complex social systems.