This document discusses arrays in programming. It defines an array as a fixed-size collection of elements of the same data type that are accessed using an index. The document describes one-dimensional, two-dimensional, and multi-dimensional arrays. It provides examples of declaring, initializing, and accessing elements of arrays. Memory layouts of two-dimensional arrays are also covered. The document concludes with some applications of arrays, such as using pointers, passing arrays to functions, and manipulating character arrays.