An evidentiary term that refers to who in litigation has the burden of proving a fact; thus for example, intellectual property rights are usually presumed legal and it is for the challenger produce evidence to show them invalid, while the holder of the rights has the burden of showing infringement. The task of overcoming the presumption is sometimes referred to as “burden of proof.” The burden of proof can shift back and forth in a case. For example, if one party has produced initial evidence that amounts to prima facie evidence of a claimed fact, the burden then shifts to the other party to rebut that evidence with evidence of its own.
In criminal cases the burden of proof of the elements of a crime always fall on the prosecution (i.e., the defendant is presumed innocent until convicted) – though the for certain defences or claims of mitigation the burden may fall on the defendant.