Term Definition: Pool
Main Description

A pool represents a Participant in a Process. It also acts as a "swimlane" and a graphical container for partitioning a set of activities from other Pools, usually in the context of B2B situations. It is a square-cornered rectangle that is drawn with a solid single line. A Pool acts as the container for the Sequence Flow between activities. the Sequence Flow can cross the boundaries between Lanes of a pool, but cannot cross the boundaries of a Pool. The interaction between Pools, for example, in a B2B context, is shown through Message Flow.

This term can be found in the OMG  Business Process Model and Notation, V2.0 specification http://www.omg.org/spec/BPMN/2.0/PDF/