Definition:
A swimlane is used in process flow diagrams. Swimlane visually distinguishes job sharing and responsibilities for sub-processes of a business process. Swimlanes may be arranged either horizontally or vertically. Swimlane diagram serves as a clean, easy-to-follow way to identify multiple actors or phases in a system. Swimlane models a better way to structure the process or to account for changing circumstances
Using the metaphor of lanes in a pool, a swimlane diagram provides clarity and accountability by placing process steps within the horizontal or vertical “swimlanes” of a particular employee, work group or department. It shows connections, communication and handoffs between these lanes, and it can serve to highlight waste, redundancy and inefficiency in a process.
Further Reading:
Book: Kanban: Successful Evolutionary Change for Your Technology Business by David J Anderson
Kanban from the Inside by Mike Burrows