Mistake
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Some unintentional act, omission or error arising from ignorance, surprise, imposition or misplaced confidence.
Code Ga. § 3117; 1 Story, Eq. Jur. § 110.
That result of ignorance of law or fact which has misled a person to commit that which, if he had not been in error, he would not have done.
Jeremy, Eq. Jur. 358.
A mistake exists when a person, under some erroneous conviction of law or fact, does, or omits to do, some act which, but for the erroneous conviction, he would not have done or omitted. It may arise either from unconsciousness, ignorance, forgetfulness, imposition, or misplaced confidence.
Bisph. Eq. § 185. And see Allen v. Elder, 76 Ga. 677, 2 Am. St Rep. 63; Russell v. Colyar, 4 Heisk. (Tenn.) 154; Peasley v. McFadden, 68 Cal. 611, 10 Pan. 179; Cummins v. Bulgin, 37 N. J. Eq. 476; Chicago, etc., R. Co., v. Hay, 119 III. 493, 10 N. E. 29; McLoney v. Edgar, 7 Pa. Co. Ct. R. 29.
Mistake of fact is a mistake not caused by the neglect of a legal duty on the part of the person making the mistake, and consisting in (1) an unconscious ignorance or forgetfulness of a fact,-past or present, material to the contract; or (2) belief in the present existence of a thing material to the contract which does not exist, or in the past existence of such a thing which bas not existed.
Civ. Code Cal. § 1577.
A mistake of law happens when a party, having full knowledge of the facts, comes to an erroneous conclusion as to their legal effect. It is a mistaken opinion or inference, arising from an imperfect or incorrect exercise of the judgment, upon facis as they really are ; and, like a correct opinion, which is law, necessarily presupposes that the person forming it is in full possession of them. The facte precede the law, and the true and false opinion alike imply an acquaintance with them.
Neither can exist without it
The one is the result of a correct application to them of legal principles, which every man is presumed to know, and is calied "law ;" the other, the result of a faulty application, and is called a "mistake of law."
Hurd v. Hall, 12 Wis. 124.
Mutual mistake is where the parties have a common intention, but it is induced by a common or mutual mistake.