Explain what is meant by a zero-indexed array.

A zero-indexed array is a type of data structure where the first element is considered at index 0 rather than 1. This means that if you have an array of 10 elements, the first element is accessed by the index 0, the second element by index 1, and so on, up to the tenth element which is accessed by index 9. This is a common practice in many programming languages such as C, C++, Java, and Python. The main advantage of zero indexing is that it simplifies the calculation of the memory address of each element, especially in languages where arrays are implemented as pointers.