Privity is the legal term for a close, mutual, or successive relationship to the same right of property or the power to enforce a promise or warranty. It is an important concept in contract law

Privity of contract

The doctrine of privity in the common law of contract provides that a contract cannot confer rights or impose obligations arising under it on any person or agent except the parties to it....

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Contract law

The principle of privity in the common law's law of contract dictates that an individual cannot sue on a contract to which he or she was not a party. A common example of the principle in operation is that if A (a consumer) buys goods from B (a retailer) which B had originally bought from C (the manufacturer) which turn out to be faulty, A cannot sue C in contract law because A has no contract with C.

U.S. federal law

In the U.S. federal law of res judicata

Res judicata

Res judicata or res iudicata , also known as claim preclusion, is the Latin term for "a matter [already] judged", and may refer to two concepts: in both civil law and common law legal systems, a case in which there has been a final judgment and is no longer subject to appeal; and the legal doctrine...

, privity is said to preclude a party to a legal action from raising an issue that either was raised or could have been raised in previous legal action. Under federal law, "concepts summarized by the term privity are looked to as a means of determining whether the interests of the party against whom claim preclusion is asserted were represented in prior litigation." Therefore, privity in federal common law

Federal common law

Federal common law is a term of United States law used to describe common law that is developed by the federal courts, instead of by the courts of the various states...

is "a convenient means of expressing conclusions that are supported by independent analysis." Because privity is actually a term to summarize a conclusion that one party was precluded, it "may exist for the purpose of determining one legal question but not another depending on the circumstances and legal doctrines at issue."