(Latin: onus pro tandi.) 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. B. 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 y. Brownson, 47 N. H. 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. 70&