Nolo's Plain-English Law Dictionary

Not Guilty

A plea entered by a defendant in a criminal case. Often erroneously confused with a claim of innocence, technically a plea of not guilty simply compels the prosecution to prove every element of the offense beyond a reasonable doubt. When the jury (or a judge sitting without a jury) acquits a defendant after trial, they return a verdict of "not guilty," which indicates their conclusion that the prosecution did not meet its burden of proving guilt beyond a reasonable doubt. (See also: reasonable doubt)
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