An activity is work that is performed within a Business Process. More specifically, an activity is a process step that can be tasks (atomic) or sub-processes (decomposable) and is executed by either a system (automated) or people (manual). All activities share common attributes and behavior such as states and state transitions.

Poster 2 of the BPMN Poster Series uses a labelled diagram to break down the lifecycle of an activity in the BPMN 2.0 specification.