The <dita> element provides a top-level container
for multiple topics when you create documents using the ditabase DTD. The
<dita> element lets you create any sequence of concept,
task, and reference topics, and the ditabase DTD lets you further nest these
topic types inside each other. The <dita> element has
no particular output implications; it simply allows you to create multiple
topics of different types at the same level in a single document.