Event

Represents something that happens. Shown as a circle. A thin border for Start, and a thick border for End.

Activity

A task or work that is performed. Represented by a rounded-corner rectangle.

Gateway

Controls the divergence and convergence of sequence flows. Shown as a diamond shape.

Sequence Flow

Shows the order in which activities will be performed. Represented by a solid line with an arrowhead.

Pool
Contains the process

Pool

Container representing an organizational entity or process, including all Lanes.

Pool
Lane 1
Lane 2

Lane

Sub-partition within a Pool to organize activities by role or department.