 In the last node of a list, the link field often contains a null reference, a special value is used to indicate the lack of further nodes.A less common convention is to make it point to the first node of the list; in that case, the list is said to be 'circular' or 'circularly linked'; otherwise, it is said to be 'open' or 'linear'.It is a list where the last pointer points to the first node.