A linear order is a way to arrange elements in a sequence where each element is comparable to every other element. In a linear order, for any two elements, one will always come before or after the other. This concept is often used in mathematics and computer science to organize data, such as in sorting algorithms. An example of a linear order is the set of natural numbers 0, 1, 2, 3, ..., where each number can be compared to any other number. Linear orders can also be represented using inequalities, such as a < b, indicating that element a comes before element b in the order.