I dont understand what exactly do you mean by calling section in a report definition. Report definition is a table/report type structure and thus will contain only columns (page lists), functions etc. Could you please elaborate more regarding the requirement.
But there is no way to include a section in the report.
The other way round is possible. Report can be included in a section by using grids.
As the discussion is going on I do not feel there is a need to call a section in a report definition as it is tabular report. However we have an option available to have custom filters via a custom section even before rendering the report. You can check the document attached to see if it helps in any way for your requirement.
Yes we can call a section in the report definition means we can display the results out from report definition in the section.
If your requirement is same you can go to the report viewer and in that we have a report body. In that we have a option called display rows using custom section. Enable that then it will ask for the section. You can give the section in that. At the run time the section will display with the rows.