Use HTML and XHTML according to their respective specifications. <dd> elements should be inside a <dl> element. They should follow a <dd> or <dt> element.
Engine scans for <dd> elements whose next sibling is not a <dd> or <dt> element
or which are not the children of a <dl> element
Not using HTML according to the specification leads to confusion for user agents and assistive technologies that rely on correct semantic information to present a coherent representation of the page.