Difficult to give a precise definition, it can be conceptualised as a set of objects together with relationships between the objects and between their attributes. In this definition, objects are parts or components of a system (i.e., sub-systems), attributes are properties of its sub-systems, and relationships are the propositions that link the various sub-systems together (e.g., the syntactic rules of a language system that interrelate components such as the phoneme, morpheme and sentence). In demarcating what constitutes a system, it is necessary to distinguish it from its context or environment. This raises the troublesome issue of setting the boundaries of a system. Thus, for example, what constitutes the limbic system, a motivational system or a child-care system? Boundary setting is an arbitrary exercise dictated by the focus of interest (e.g., the mother-infant dyad or the father-infant dyad, both of which together can be redefined as a triadic system and which again can be incorporated into a family system)
See Closed system, Complex system, Complexity, Circular (or non-linear) causality, Dynamical system, Ecological systems theory, General system theory (GST), Linear dynamical systems, Non-linear dynamical systems, Open system, Organization, Systems approach, Systemogenesis