|Language and punctuation / Titles and headings|
There is no line break element or equivalent in DITA.
Line breaks are formatting constructs, so in general, DITA mark-up doesn't provide for them. However, it's not quite so clear cut. Despite working to the ideal that content should be separated from form, DITA does provide for a good deal of form mark-up.
Table column widths can be specified in DITA, even though that's form. Image sizes can be specified in DITA, and that too is form.
It is possible to use these loopholes in the separation of content and form to make possible things such as line breaks in titles. For example, a workaround is to place a one pixel by one pixel image within the title, and set the image element's placement attribute to break. This will cause, in most outputs, the title to be displayed with text before the image displayed on a different line to text following.
You must avoid the temptation to use such workarounds in an attempt to introduce form into DITA content.