An application function is defined as a representation of a coherent group of internal behaviour of an application component.

An application function describes the internal behaviour of an application component. The function's internal behaviour is invisible to the user of an application component.

An application function's behaviour is exposed externally through one or more services. An application function may realize application services.

Application services of other application functions and infrastructure services may be used by an application function.

An application function may access data objects.

An application component may be assigned to an application function.

The name of an application function should preferably be a verb ending with "-ing"; e.g., "accounting".

Category: Application Layer and Behaviour aspect

Examples: Accounting, Billing, Policy Creation, Calculate Premium, Financial Administration.

Typical Relationships:
*Used by - application service
Triggering - application function
Access - data object
Assignment - application component

Source: Archimate 2.1, Chapter 4 Application Layer