Estoppel is a common law doctrine which, when it applies, prevents a litigant from denying the truth of what was said or done. The doctrine of estoppel by deed (also known as after-acquired title) is a particular estoppel doctrine in the context of real property transfers. Under the doctrine, the grantor of a deed (generally the seller of a piece of real property) is estopped (barred) from denying the truth of the deed. The doctrine may only be invoked in a suit arising out of the deed, or involving a particular right arising out of the deed.
While rooted in warranty deeds, estoppel by deed has been extended to affect quitclaim deeds if the deed represents that the grantor actually had title.