A System Context Diagram is a visual representation of the components and actors within a system and their interactions. It provides a high-level view of the system and its environment, showing the boundaries of the system and how it interacts with external entities. The diagram is used to identify the system
From Wikipedia
A system context diagram in engineering is a diagram that defines the boundary between the system, or part of a system, and its environment, showing the entities that interact with it. This diagram is a high level view of a system. It is similar to a block diagram.