Circular reference refers to a formula in a spreadsheet that either directly or indirectly depends on itself. This creates a loop where the formula keeps referencing itself, leading to an infinite loop or erroneous calculation.

Causes and Examples of Circular Reference:
- A common example of a circular reference is when a cell's formula includes a reference to the cell itself. For example, if cell A1 has a formula that says "=A1+1", it creates a circular reference because it is trying to add 1 to its own value.
- Circular references can also occur when multiple cells refer to each other in a cycle. For instance, if cell A1 refers to cell B1, which in turn refers back to cell A1, a circular reference is formed.

Characteristics of Circular Reference:
- Circular references can cause incorrect calculations in spreadsheets because the formula keeps recalculating without reaching a final value.
- They can result in endless loops and slow down the performance of the spreadsheet.
- Circular references are often displayed with an error message or warning in spreadsheet software to alert the user.

Impact and Solutions:
- Circular references can lead to erroneous results and make it difficult to identify the source of the error.
- To resolve circular references, the formula causing the loop needs to be modified or removed.
- Spreadsheet software often provides tools to help identify and fix circular references, such as tracing precedents and dependents, or using iterative calculations.

Conclusion:
In summary, a circular reference is a formula that either directly or indirectly depends on itself. It can create an infinite loop and cause erroneous calculations in spreadsheet software. Identifying and resolving circular references is important to ensure accurate and reliable results in mathematical calculations.