ESTOPPEL

A rule of law that when person A, by act or words, gives person B reason to believe a certain set of facts upon which person B takes action, person A cannot later, to his (or her) benefit, deny those facts or say that his (or her) earlier act was improper. A 1891 English court decision summarized estoppel as "a rule of evidence which precludes a person from denying the truth of some statement previously made by himself".