In U.S. law, the writ of supersedeas is a stay of execution on a civil judgment pending an appeal.
"Execution" in this sense refers to all the legal means to collect a money judgment. It generally means the court will not enter any orders to facilitate collection, such as writs preventing the transfer of funds or property (writ of attachment) or directing third parties not to pay funds owed to the defendant (writ of garnishment) or directing the sheriff to assist in the seizure of property (writ of execution).
The writ of supersedeas is issued by the trial judge before the case is passed on to an appellate court. To get the writ, a judgment debtor must put up a bond: cash or surety (the promise of a third party) to defray interest and attorney's fees caused by the delay of the appeal.
In United States common law, the judgment debtor is not given the option to voluntarily pay the judgment and proceed with the appeal. Technically, paying the judgment is deemed a waiver of the right to appeal, and as a practical matter, it is seen as a way of evading the bond requirement and shifting the burden of a frivolous appeal to the prevailing party.
Since the amount of the bond is frequently tied by statute to the amount of the judgment—it is often double the amount of the judgment—it can be a serious deterrent against frivolous appeals. If the judgment is truly enormous, such as the extremely large judgments sometimes entered in class action personal injury lawsuits, the requirement of a supersedeas bond may prevent even the biggest corporations from filing an appeal. With the occasional ridiculously large judgment in the billions, courts have had to consider whether statutes making a supersedeas bond mandatory are consistent with the constitutional requirement of due process.