A bar or impedlment rais-ed by the law, which precludes a man from alleging or from denying a certain fact or state of facts, in consequence of his previous allegation or denial or conduct or admission, or in’consequence of a final adjudication of the matter in a court of law. Demarest v. Hopper, 22 N. J. Law, 619; Martin v. Rail-road Co., 83 Me. 100, 21 AU. 740; Veeder v. Mudgett, 95 N. Y. 295; South v. Deaton, 113 Ky. 312, 68 S. W. 137; wilkins v. Suttles, 114 N. C. 550, 19 S. E. 606