Added whole-column references such as A:A and $A:$C and whole-row references such as 2:2, including on another sheet. The reference covers the rows (or columns) through the last populated cell in the referenced columns (or rows), so SUM(A:A) adds the column and ROWS(A:A) counts its populated extent. Copying a formula moves a whole-column reference by column only. A whole row or column containing the formula itself is a circular reference.
Added whole-column and whole-row references to Spreadsheets
Formulas can refer to A:A or 2:2. The reference covers the rows or columns through the last populated cell in that span.