•An address or pointer that changes when the target item is moved or the relationship to it has changed. For example, in a spreadsheet, a cell with a relative reference changes its formula when copied elsewhere. Contrast with absolute reference.

•An address or pointer that does not change. For example, in a spreadsheet, a cell with an absolute reference does not change even if copied elsewhere.

•A mixed cell reference is either an absolute column and relative row or absolute row and relative column. When you add the $ before the column letter you create an absolute column or before the row number you create an absolute row.

Relative Referencing, Absolute Referencing, and Mixed Referencing are three methods used in Microsoft Excel to refer to cells or ranges in formulas.

Relative Referencing:
- When a cell reference is copied or moved to a new cell, it changes its reference based on the relative position of the new cell.
- It is the default type of referencing used by Excel.
- The formula will adjust its reference automatically based on its relative position to the new cell location.
- It is indicated by no symbol or a regular reference symbol (e.g. A1).

Absolute Referencing:
- When a cell reference is fixed and does not change its reference when copied or moved to a new cell, it is called an absolute reference.
- It is represented by a dollar sign ($) before the column letter or row number or both (e.g. $A$1).
- Absolute referencing is useful when you want to refer to a fixed cell in your formula, such as a tax rate or a constant value.

Mixed Referencing:
- When a cell reference is partially fixed and partially changes its reference when copied or moved to a new cell, it is called a mixed reference.
- It is represented by a dollar sign ($) before either the column letter or the row number (e.g. $A1 or A$1).
- Mixed referencing is useful when you want to fix either the column or row reference of a cell, but not both.

In summary, relative referencing adjusts the reference based on its relative position; absolute referencing does not change the reference when copied or moved to a new cell; mixed referencing partially changes the reference. Each type of referencing has its own specific use and can be combined in different ways to create more complex formulas in Excel.