Apple iWork '08 - Manual (Page 59)

Chapter 2 Getting Started with Numbers 59
Introducing Tables
The Loan Comparison table in the template you’re using has a header row, a header
column, and a footer row.
Although they’re optional, header rows, header columns, and footer rows are
very useful.
 Header rows and header columns let you assign names to rows and columns and then
use those names to refer to cells in formulas. They’re also used to label data in charts.
 Footer rows are useful for highlighting values derived from other values in the table.
Footer row (the bottom
row, even when you add
new rows)
Header row (the topmost
cell in every column)
Header column (the
leftmost cell in every row)