Estoppel

Estoppel, a bar or impediment to the exercise of some right, arising from a man's own act or the act of some person, through whom he claims. There are three kinds of estoppel, viz.: - (1) Estoppel bg record, as letters patent, pleadings, etc. Thus, in an action against a patentee by his assignee, the patentee is estopped from pleading that the patent is invalid. (2) By matter of writing as by deed, etc., parties and privies are stopped from alleging anything contrary to the deed. (3) By matter in pais (in the country), that is, transactions not evidenced by record or writing as livery, entry, acceptance of rent, etc. Thus, after acceptance of rent a landlord cannot treat his lessee as a trespasser.