Confession of error is a party's admission, express or implied, made on appeal, that the court below committed an error in his favor, or prejudicial to the rights of an adverse party.
The following is an example of a case law referring to confession of error:
A confession of error by a litigant is an important factor to take into account in studying a record. It may disclose an intervening decision on a question of law that undermines the lower court's conclusion; it may disclose perjury by an important witness or newly discovered evidence; it may disclose other factors which weaken the conclusion of the lower court; or it may disclose a maneuver to save one case at the expense of another. [Casey v. United States, 343 U.S. 808, 811-812 (U.S. 1952)].