term:

Erie Doctrine

erie doctrine n

[from the Supreme Court case Erie Railroad Co. v. Tompkins, which resulted in definition of the doctrine]
: a doctrine that a federal court exercising diversity jurisdiction over a case for which no federal law is relevant must apply the law of the state in which it is sitting called also Erie Rule see also Erie Railroad Co. v. Tompkins in the Important Cases section

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.