Predefined process
A 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.
Easily confused with
- Weak entityA weak entity: a kind of thing that can only be identified through another entity it belongs to, such as the items on an order. It is drawn as a rectangle with a double outline.
- ProcessA step in which something is done: a calculation, an assignment or any other operation. The process symbol is a plain rectangle with the step written inside.
How to read it
The box stands for a whole group of operations shown in detail elsewhere, or not drawn at all: a library routine, a function call. ISO 5807:1985 defines it as a named process of one or more operations or program steps specified elsewhere, for example a subroutine or a module. The 1970 American standard adds that elsewhere means outside this set of flowcharts.
That is what separates it from a striped Process box, the other way to point to more detail: a stripe across the top means the detail is in the same set of charts.
Also searched as: flowchart predefined process, predefined process symbol, subroutine symbol.
Look-alikes
A plain Process rectangle has no side lines. On an ER diagram a rectangle inside a rectangle is a weak entity. IBM’s manual notes that a predefined process symbol cannot be striped.
Read next
- Next in Flowchart symbolsDocumentA document or printed report: data on paper or another human-readable medium. The symbol is a rectangle whose bottom edge is a wave.
- In BPMN symbolsSub-processA 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.
More flowchart symbols
The same shape elsewhere
Browse symbols drawn with lines or squares and rectangles.
Sources
- Information processing: Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts, ISO 5807:1985, first edition (preview pages), International Organization for Standardization (iTeh Standards preview), Section 9.2.2.1
- Flowchart Symbols and Their Usage in Information Processing, ANSI X3.5-1970, adopted for federal use as FIPS PUB 24, American National Standards Institute; National Bureau of Standards (NIST), Sections 3.3.2.2 and 4.9
- Flowcharting Techniques, IBM Data Processing Techniques, Form C20-8152, International Business Machines Corporation (bitsavers.org), Special processing symbols; striping
- 10.3: Flowcharting, Kenneth Leroy Busbee, CSP31A C Programming, Delta College (LibreTexts Engineering), Module Call
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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