Many typical spreadsheet models are built in a hierarchical fashion. For example, in a monthly budget worksheet, you might have a column for each month of the year, followed by a totals column. For each line item in your budget, the totals column adds the values in each month column. In this kind of structure, you can describe the month columns as subordinate to the totals column because their values contribute to the outcome of the totals column.
The line items also can be set up hierarchically, with groups of expense categories contributing to category totals. Excel can turn worksheets of this kind into outlines.