A supplemental appropriation refers to:

A supplemental appropriation specifically refers to additional funds that are authorized beyond the amounts that have already been approved in the annual budget. These funds typically arise from unanticipated revenue sources or expenditures that were not accounted for in the original budget. This mechanism allows governmental entities to respond effectively to unexpected financial situations, ensuring that necessary services can continue without interruption or compromise.

When funds become available, or when expenses exceed initial predictions, it is essential for entities to seek a supplemental appropriation to make use of these resources legitimately. This process ensures transparency and accountability in financial management, as any changes to the budget require approval and proper documentation, maintaining the integrity of the budgetary process.

In this context, the other options do not accurately define a supplemental appropriation, as they either limit the definition to annual budgets, imply permanence when supplemental appropriations may be temporary, or focus on specific outcomes like debt repayment instead of the broader financial adjustments a supplemental appropriation encompasses.