Payments returned to the government that were made in error. They are credited to the appropriation originally charged.
Either (1) the return of money that the government improperly collected or collected in excess of the amount owed (for example, refund is money owed to taxpayers by the government when their total tax payments are greater than their total tax) or
(2) money returned as an appropriation by outside sources for payments that the government made in error, overpayments, or adjustment for previous amounts disbursed.
Industrial fund amounts transferred on a nonexpenditure basis which represent the transfer of amounts associated with prior year efforts or sales. These amounts usually represent the transfer of revenue collected through stabilized rates which: (1) were in excess of [then] current year costs or
(2) otherwise exceeded the purpose for which initially intended. These transfers are generally made to appropriated funds and provided for in a general provision contained in the applicable annual appropriation act.
Refunds has been defined 4 different ways in documents like A Glossary of Terms Used in the Federal Budget Process, A Glossary of Terms Used in the Federal Budget Process, DoD Financial Management Regulation Glossary, and 1 more.