Sub-process
A step that has a process of its own inside it. A collapsed sub-process is a rounded rectangle with a small square holding a plus sign at the bottom centre.
Easily confused with
How to read it
BPMN 2.0.2 calls a sub-process a compound activity: one that can be broken down into finer detail. Collapsed, it looks like a Task with the plus marker, and its detail is drawn elsewhere. Expanded, the box is enlarged and the detail is drawn inside its boundary. Politecnico di Milano’s exercise book describes the collapsed box as a compressed version that is expanded separately, and Camunda’s reference says the plus sign means a detailed sequence is stored behind it.
Also searched as: bpmn sub-process, bpmn subprocess, collapsed sub-process, plus sign bpmn, sub-process symbol.
Other borders
The standard keeps other borders for other kinds of sub-process: a thick border for a call activity, a dotted one for an event sub-process and a double one for a transaction.
Look-alikes
In a flowchart, a step defined somewhere else is a predefined process, a rectangle with a line near each end. A plus sign inside a diamond is a Parallel gateway.
Read next
- Next in BPMN symbolsExclusive gatewayA point where the process takes exactly one of several paths. The exclusive gateway is a diamond, often with an X inside.
- Both stand for a step defined in more detail elsewhere.Predefined processA named process that is defined somewhere else, such as a subroutine or module. The symbol is a rectangle with an extra vertical line just inside each end.
More BPMN symbols
The same shape elsewhere
Browse symbols drawn with crosses or squares and rectangles.
Sources
- Business Process Model and Notation (BPMN), Version 2.0.2, OMG document formal/2013-12-09, December 2013 (also ISO/IEC 19510), Object Management Group, Section 10.3.5 and Table 7.2
- Business Process Modeling Notation (BPMN): Modeling Exercises, Cinzia Cappiello, Pierluigi Plebani and Monica Vitali, v.1.1, 2016 (CC BY-SA), Politecnico di Milano, Chapter 1, 1.2 Subprocesses
- BPMN 2.0 Symbols: a complete guide with examples, BPMN reference, adapted from Freund and Rücker, Real-Life BPMN, Camunda, Activities: Subprocess
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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