Refund
A payment from the government for an individual's overpaid taxes. An individual in this situation is said to be "over-withholding." Federal income tax refunds are not taxable.
Investopedia Commentary
In short, when the government owes you back some of the taxes you paid throughout the year.
See also: Direct Tax, Earned Income Credit, Income Tax, Refundable Credit, Withholding
refund