What is Burden Of Proof?

Legal Definition
The burden of proof (Latin: onus probandi) is the duty of a party in a trial to produce the evidence that will shift the conclusion away from the default position, to that party's own position. In a legal dispute, one party is initially presumed to be correct and gets the benefit of the doubt, while the other side bears the burden of proof. When a party bearing the burden of proof meets their burden, the burden of proof switches to the other side. Burdens may be of different kinds for each party, in different phases of litigation. The burden of production is a minimal burden to produce at least enough evidence for the trier of fact to consider a disputed claim. After a litigant has met the burden of production and their claim is being considered by a trier of fact, they have the burden of persuasion, that enough evidence has been presented to persuade the trier of fact that their side is correct. There are different standards of persuasiveness ranging from a preponderance of the evidence, where there is just enough evidence to tip the balance, to proof beyond a reasonable doubt, as in United States criminal courts.

The burden of proof is usually on the person who brings a claim in a dispute. It is often associated with the Latin maxim semper necessitas probandi incumbit ei qui agit, a translation of which in this context is: "the necessity of proof always lies with the person who lays charges."

The party that does not carry the burden of proof carries the benefit of assumption of being correct, they are presumed to be correct, until the burden shifts after presentation of evidence by the party bringing the action. An example is in an American criminal case,where there is a presumption of innocence by the defendant. This party needs no evidence to support its claim. Fulfilling the burden of proof effectively captures the benefit of assumption, passing the burden of proof off to another party.
-- Wikipedia
Legal Definition
Generally used to describe the threshold that a party seeking to prove a fact in court must reach in order to have that fact legally established. For example, in criminal cases, the burden of proving the defendant’s guilt is on the prosecution, and they must establish that fact beyond a reasonable doubt. In civil cases, the plaintiff has the burden of proving his case by a preponderance of the evidence.
Legal Definition
This phrase is employed to signify the duty of proving the facts in dispute on an issue raised between the parties in a cause.

2. The burden of proof always lies on the party who takes the affirmative in pleading. 1 Mass. 71, 335; 4 Mass. 593; 9 Pick. 39.

3. In criminal cases, as every man is presumed to be innocent until the contrary is proved, the burden of proof rests on the prosecutor, unless a different provision is expressly made by statute. 12 Wheat. See Onus probandi.
-- Bouviers Law Dictionary
Legal Definition
(Lat onus probandi.) In the law of evidence. The necessity or duty of affirmatively proving a fact or facts in dispute on an issue raised between the parties in a cause. Willett v. Rich, 142 Mass. 356, 7 N. E. 776, 56 Am. Rep. 684; Wilder v. Cowles, 100 Mass. 490; People v. McCann, 16 N. Y. 58, 69 Am. Dec. 642. The term "burden of proof" is not to be confused with "prima facie case." When the party upon whom the burden of proof rests has made out a prima facie case, this will, in general, suffice to shift the burden. In other words, the former expression denotes the necessity of establishing the latter. Kendall v. Brownson, 47 N. BL 200; Carver v. Carver, 97 Ind. 511; Heinemann v. Heard, 62 N. Y. 455; Feurt v. Ambrose, 34 Mo. App. 366; Gibbs v. Bank, 123 Iowa, 736, 99 N. W. 703.
-- Black's Law Dictionary
Legal Definition
The onus of establishing certain facts by the production of evidence. See 33 L. R. A. (N. S.) 1089; also 71 Am. St. Rep. 169.
-- Ballentine's Law Dictionary