System of Systems - the meaning of of

We present distinguishing characteristics (i.e. autonomy, belonging, connectivity, diversity, and emergence), that can help us to recognize or to realize a System of Systems (SoS). The principle differentiation that we make between a thing being either a `system' or a SoS focuses on the nature of a system's composition. We will distinctly define this set of distinguishing characteristics which will include a set of cross references from our literature research where we believe others are articulating our chosen differentiating characteristics. We conclude by summarizing the difference in these terms in a fundamental sense, one that impacts their structure, behavior and realization, and the distinction comes from the manner in which parts and relationships are gathered together and therefore in the nature of the emergent whole