A mixed cell reference is a combination of relative and absolute cell references. In spreadsheets, cell references are used in a variety of commands, charts, functions and formulas.
In Microsoft Excel, there are three types of cell references: relative, absolute and mixed. Cell references are relative by default. This means that when a formula is copied from one cell to another cell or multiple cells, it changes to match the cell reference of the new cells. For instance, when users copy the formula = A3+B3 from cell C3 to cell C4, the formula in C4 will adjust one cell down to = A4+B4. If users want to keep the original cell reference after copying the formula, they place the $ sign in front of the columns (A and B) as well as row 3, which becomes (=$A$3+$B$3). This is called an absolute reference.
An absolute reference remains the same when a formula is copied from one cell to another cell or cells.
Although it is rare to use mixed cell references, the need may arise when users need to make a cell reference mixed. In that case, they lock either the row or the column by preceding it with the $ sign as in $A3 or B$3.