What is "prosecution history estoppel"

n. (context legal English) In United States patent law, the circumstance under which a person who has filed a patent application, and then made amendments to the application to accommodate the patent law and secure issuance of the patent, is prevented from bringing a cause of action for infringement of the patent where the allegedly infringing acts falling within the matter disclaimed by the amendment.

Prosecution history estoppel, also known as file-wrapper estoppel, is a term used to indicate that a person who has filed a patent application, and then makes narrowing amendments to the application to accommodate the patent law, may be precluded from invoking the doctrine of equivalents to broaden the scope of their claims to cover subject matter ceded by the amendments. Although primarily a U.S. term, questions of whether, or the extent to which the prosecution history should be relevant for determining the extent of protection of a patent also arise outside the U.S.