A cell reference locked with dollar signs ($A$1) so it doesn't shift when you copy the formula.
Try it with AIAn absolute reference fixes a row, column, or both using $. $A$1 locks both; A$1 locks the row; $A1 locks the column. This keeps a formula pointing at the same cell when filled across or down.
=B2*$F$1 (← $F$1 stays put when copied down)Select the reference in the formula bar and press F4 to cycle through $A$1, A$1, $A1, A1.
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