BPMN diagrams consist of two main types of elements: nodes and connections. In BPMN 2.0, nodes are represented with data, flow objects, swim lanes and artifacts whereas connections are represented with connecting objects.
The central and most complex category of BPMN elements is flow objects. This consists of activities, gateways and events. An activity is a generic type of work that an individual or company performs. BPMN defines two major types of an activity: Tasks and Sub-processes. A gateway is used to split or merge multiple process flows. It determines the branching, forking, merging and joining of a business process’s path. The ‘event’ represents something that starts a process, happens during the process, or represents an end state of a process.
Swim lanes are used to define and organize processes. They consist of two elements, pools and lanes. Pools represent a process participant and may include a process, whereas lanes are used to organize work within a process.
Data elements provide information about what activities require to be performed and what they produce.
Artifacts are used to provide additional information about processes, however they do not affect the flow of a process. The most common artifact is a comment.
All of these BPMN categories of elements are linked with each other by using one of the proper connecting objects.