Answer: In discipline such as computer science, a sequence or a list is referred to as an abstract data type which tends to represent a countable no. of the ordered values, under which the same value or content may tend to occur or pops up more than once. Instance of any list is referred to as a computer representation or display of mathematical concept or notion of finite sequence or order.
The abstract data type needs to declare signature of an operations essential for any particular or specific data type. It does not tend to have an implementation.