Like flowcharts, BPMN (Business Process Model and Notation) diagrams use a set of standard symbols. Each shape conveys a specific meaning and business context, where it’s most appropriate.
Swimlanes (or swimlane diagrams) are used to organize aspects of the process.
Swimlanes are visual elements used in flow charts, or process flow diagrams, that visually separates job-sharing and responsibilities of sub-processes within a business process. Swimlanes visually group objects into lanes, with each aspect of a process will be added to a separate lane. Swim lanes can be arranged either horizontally or vertically.
Swimlane diagrams not only organize activities into separate categories, but they can also reveal delays, inefficiencies, and workers responsible for each step in the process.
BPMN Swimlane Symbol
Hope this helps!