A persistent list is a data structure that allows access to previous versions of the list after modifications. Unlike traditional lists, which overwrite their contents, persistent lists maintain all historical states, enabling users to retrieve any version without losing the current one. This feature is particularly useful in functional programming, where immutability is a key principle. In a persistent list, operations like adding or removing elements create a new version of the list while keeping the original intact. This is achieved through techniques like structural sharing, which minimizes memory usage by reusing parts of the existing structure. Examples of languages that support persistent lists include Haskell and Scala.