Unilateral mistake
Defined in 1 dictionary — Black's (1910)
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
A mistake or misunderstanding as to the terms or effect of a contract, made or entertained by one of the parties to it but not by the other. Green v. Stone, 54 N. J. Eq. 387, 34 Atl. 1099, 55 Am. St. Rep. 577.
Defined under Unilateral in Black's Law Dictionary.