Glossary
Relation back
A rule that treats a later-filed amendment as if it had been filed on the date of the original complaint, which can save a claim from being too late.
When a person updates their lawsuit by adding a new claim or a new defendant, the relation-back rule decides whether that update counts as timely. If the new claim grows out of the same events as the original complaint, it usually relates back. Adding a new defendant requires more, including that the new defendant knew about the lawsuit in time and understood they would have been sued except for a mistake. Relation back is a common way to fix naming errors without losing the case to a missed deadline. The rules are technical and vary between federal and state courts.