What is Linked list?

Answer 1

A series of nodes which may have two or three parts which includes value and address of their previous and next nodes

Answer 2

Shamra is right. It is a data structure that contains many elements where element points to the next one. When the element points to the element before then it is a double linked list.
Imagine people standing in a row. Each person knows the one before (single linked list) or the guy behind him (double linked list)

Answer 3

additional:
linkedlist knows only its first element and if declared its lenght.