Final answer:
The start/stop symbol in a systems flowchart does not represent an external entity; it simply indicates the initiation or conclusion of a process.
Step-by-step explanation:
In the context of systems flowcharts, the start/stop symbol is generally not considered an external entity. The start/stop symbol is used to indicate the beginning and end of a process within the flowchart. External entities, on the other hand, are typically represented by different symbols such as rectangles or parallelograms and represent sources or destinations of data that exist outside the system being diagrammed.