What is the difference between doubly linked list and circular linked list?

A doubly linked list is a linked list in which each node knows where both of its neighbors are.

A circular linked list is a linked list in which the "tail" of the list is linked to the "root". (Note that both the tail and root of the list are undefined/arbitrary in a circular linked list)

Doubly linked lists are actually not necessarily related to circular linked list (aside from both being based on a linked list structure). In fact, you can have a circular doubly linked list, where each node knows where both of its neighbors are andwhere the list wraps around to connect to itself.