A doubly linked list is a type of data structure that consists of a sequence of nodes. Each node contains three parts: a data field, a pointer to the next node in the sequence, and a pointer to the previous node. This allows traversal of the list in both directions, making it more flexible than a singly linked list, which only allows movement in one direction. In a doubly linked list, you can easily insert or remove nodes from both ends or anywhere in the list. This structure is useful in various applications, such as implementing deques or browsers' history, where you need to navigate back and forth efficiently.