Enterprise systems engineering (ESE) is the discipline that applies systems engineering to the design of an enterprise. As a discipline, it includes a body of knowledge, principles, and processes tailored to the design of enterprise systems.
It accomplishes all of the tasks of "traditional" systems engineering, further informed by an expansive view of the context (political, operational, economic, technological, interacting systems, etc.) in which the system(s) under consideration are being developed, acquired, modified, maintained, or disposed of.
Enterprise systems engineering may be required when the complexity being faced (due to scale, uncontrollable interdependencies, and other uncertainties) breaks down the assumptions upon which textbook systems engineering is based, such as requirements being relatively stable and well-understood, a system configuration that can be controlled, and a small, easily discernable set of stakeholders.