Thank you for your feature request.
offers built-in support only for ordered and unordered list creation.
These types of elements are widely used by the users and the browser
offers built-in commands for them which we enhanced further with custom
code. The InsertOrderedList and InsertUnorderedList commands are listed
in the following MSDN article: Command Identifiers
the browser does not offer a command for Definition List creation and
RadEditor does not offer such a tool too, the only possible way is to
implement your own custom button tool
that will insert and manipulate the Definition lists.
the Telerik team