An acquittal is a release, absolution, or discharge of an obligation or liability.
Its main use is in criminal law, where an acquittal is the finding that a defendant is "not guilty." This means only that the prosecution has been unable to prove that there was sufficient evidence to prove beyond a reasonable doubt that the defendant committed the crime for which he was charged. It should not be viewed as proof of the defendant's innocence. This fact has created anomalies where a person has been not guilty of a crime, may still be held civilly responsible for the act. The most notable case in which this occurred was in the OJ Simpson murder trial where he was found not guilty of the murder of his wife, but found responsible for her death in a civil wrongful death judgment. The anomaly is created due to the differing standards of proof required between civil and criminal jurisdictions (on the Preponderance of the evidence vs beyond reasonable doubt).
In Scottish law, a jury is able to return a verdict of "Not Proven" as well as the familiar "not guilty" and "guilty" verdicts. This verdict is designed to indicate that the jury is not convinced of the defendant's innocence, but there is insufficient evidence for a conviction. This third verdict is sometimes called the Scottish verdict, and there have been calls for its adoption in other common law jurisdictions.