refund (v.) Look up refund at Dictionary.com
"to give back, restore," 1432 (earlier "to pour back," late 14c.), from O.Fr. refunder "restore," from L. refundere "give back, restore," lit. "pour back," from re- "back" + fundere "to pour" (see found (2)). Specifically of money from 1553. The noun is 1866, from the verb.