Nesting dimensions places one dimension inside another. It allows a report to display more than one row or column dimension at a time.
Note: You can also reorder dimensions using Set dimension order. To open the Set dimension order page, click the "Set dimension order" button on the toolbar.
In the screenshot below, an Other dimension has been dragged to the edge of the row dimension. The edge of the row dimension has changed color to show that the dragged dimension can be dropped and nested into it.