A Boundary is a stereotyped Class that models some system boundary, typically a user interface screen. It is used in the conceptual phase to capture users interacting with the system at a screen level (or some other boundary interface type). It is often used in Sequence and Robustness (Analysis) diagrams. It is the View in the Model-View-Controller pattern.
To create a Boundary, click on the link.
Tip: Use Boundary elements in analysis to capture user interactions, screen flows and element interactions (or 'collaborations').