Architecting and designing : Business Process Analysis (BPA) : BPMN : Introduction to BPMN : Swimlanes and Pools
  
Swimlanes and Pools
A pool is a graphical container for partitioning a set of processes and tasks from other pools, usually in the context of B2B situations. A Lane is a sub-partition within a Pool and extends the entire length of the Pool either vertically or horizontally. Lanes are used to organize and categorize activities within a Pool. Typically, an organization is represented by a pool, and the departments within the organizations are represented by lanes. A pool can represent other things besides an organization, such as a function, an application, a location, a class, or an entity.
See also Modeling groups, pools, and lanes on business process diagrams.
See also
Introduction to BPMN