Reversible error

In law, a reversible error is an error by the trier of law (judge) or the trier of fact (the jury or the judge if it is a bench trial) or malfeasance by one of the trying attorneys, which results in an unfair trial. It is to be distinguished from harmless errors that do not rise to a level that bring the validity of the judgment into question and thus do not lead to a reversal upon appeal.