System Context (glossary)
(1) Describes the system relationships and environment, resolved around a selected system-of-interest. (Flood and Carson 1993)
(2) Diagram defining the highest level view of a system in its environment. (Flood and Carson 1993)
(1) and (2) Flood, R.L. and E.R. Carson. 1993. Dealing with complexity: An introduction to the theory and application of systems science, 2nd ed. New York, NY, USA: Plenum Press.
Definition (1) describes the reason for considering context.
Definitions (2) relates context to a context diagram. This is most common way in which context is express in systems engineering. A number of context diagram notations are available.