Network science
The study of complex systems whose behavior and responses are determined by exhcanges and interactions between subsystems across a well-defined (possible dynamics) set of pathways, The central point is that the behavior of a network is determined both by the pathways (structure) and by the exchanges and interactions (dynamics). Moreover the structure itself may be (and usually is) dynamics. This is a flexible definition that allows flexible interpretation in the various applications domains. (Network Science, National Research Council of the National Academies)
Network Science in Three Important Ways
History of Network Science