In Excel, the dollar signs in a cell reference indicate an absolute reference. An absolute reference means that the cell reference will not change when the formula is copied or moved to another cell.

For example, if you have a formula that references cell A1 and you copy that formula to cell B1, the reference to A1 will automatically change to B1. However, if you use an absolute reference with dollar signs like , the reference will remain as A1 even if you copy the formula to another cell.

When you use a dollar sign before the column letter and row number like , it means that both the column and row are absolute references. This means that the reference will not change when the formula is copied or moved to another cell.

On the other hand, when you use a dollar sign before either the column letter or the row number like or , it means that only the column or row is an absolute reference. This means that the reference will change when the formula is copied or moved to another cell, but the column or row with the dollar sign will remain the same.

So, is an absolute reference to cell A1, while is an absolute reference to column A and is an absolute reference to row 1.

1. Use dollar signs in a cell reference to indicate an absolute reference.
2. An absolute reference means that the cell reference will not change when the formula is copied or moved to another cell.
3. Use
   Code:

   $A$1

   to indicate that both the column and row are absolute references.
4. Use
   Code:

   $A1

   or
   Code:

   A$1

   to indicate that only the column or row is an absolute reference.