# api-domain reference module

Defines the elements referring to API items within API topics or other DITA topic types, such as concept or task.

#### Description

The api-domain topic type packages several elements, such as <apioperation> or <apipackage> elements. These elements allow the writer a consistent way to reference other topic types operations or packages.

The api-domain topic contains the following elements:

- apiclassifier
  The <apiclassifier> element is a reference to a classifier.
- apioperation
  The <apioperation> element is a reference to an operation.
- apipackage
  The <apipackage> element is a reference to a package.
- apivalue
  The <apivalue> element is a reference to a value.

Parent topic: Generic API topic types