A linked list is a linear data structure consisting of a collection of nodes, where each node contains a data field and a reference (or pointer) to the next node in the list. Unlike arrays, linked lists do not store elements in contiguous memory locations, and the order of the elements is not given by their physical placement in memory. Instead, each element points to the next element in the list, allowing for easy insertion and removal of nodes at any point in the list without the need for reallocation or reorganization of the entire structure.

Linked lists are among the simplest and most common data structures and can be used to implement several other common abstract data types, including lists, stacks, queues, associative arrays, and S-expressions. They are particularly useful when the size of the data is unknown or when the data needs to be frequently inserted or removed from the list.

Linked lists can be implemented using references together with records in languages that do not support abstract data types or templates, while in languages that support abstract data types or templates, linked list ADTs or templates are available for building linked lists.

Overall, linked lists are a fundamental data structure in computer science and are widely used in various applications, such as operating systems, compilers, and databases.