A more thorough explanation:

Estoppel per rem judicatam is a legal term that refers to the binding effect of a judgment on later controversies between the parties involving a different claim from that on which the original judgment was based. It is also known as collateral estoppel, issue preclusion, or estoppel by judgment.

For example, if a court has already decided that a defendant is liable for damages in a car accident case, the defendant cannot later argue in a different case that they were not at fault for the accident. This is because the issue of fault has already been litigated and determined in the first case, and the defendant is estopped from relitigating the same issue in a different case.

There are different types of collateral estoppel, including:

• Defensive collateral estoppel: estoppel asserted by a defendant to prevent a plaintiff from relitigating an issue previously decided against the plaintiff.
• Offensive collateral estoppel: estoppel asserted by a plaintiff to prevent a defendant from relitigating an issue previously decided against the defendant.
• Nonmutual collateral estoppel: estoppel asserted either offensively or defensively by a nonparty to an earlier action to prevent a party to that earlier action from relitigating an issue determined against it.

Overall, estoppel per rem judicatam is an important legal principle that helps to promote finality and consistency in the judicial system.