A more thorough explanation:

Definition: Relation back is a legal doctrine that allows an act done at a later time to be treated as if it occurred at an earlier time, under certain circumstances.

For example, in federal civil procedure, if an amended pleading is filed, it may relate back to the time when the original pleading was filed for purposes of the statute of limitations. This means that even though the amended pleading was filed later, it will be treated as if it was filed at the same time as the original pleading.

Another example of relation back is when a court applies the doctrine to a case. This means that the court treats an act done at a later time as if it occurred at an earlier time.

Overall, relation back is a legal concept that allows for certain actions to be treated as if they occurred at an earlier time, which can have important implications for legal cases.