By default, every topic generated is of type concept. However, you can specify a different topic type as the default: topic, task, reference, glossary, or a custom type.
To specify a different default topic type:
[DITAOptions] ; DefTopic = name of topic type to use, default "concept" DefTopic = topic
You can override the default topic type with a DITATopic marker in the topic, or by assigning a different topic type to a paragraph format used in the topic.
To specify a different default topic type for a given chapter, include the DefTopic setting in a chapter configuration file named for the file; see §42.1.1 Providing configuration files for individual ditamaps.