An array is a contiguous block of memory that stores elements of the same data type. Arrays allow storing and accessing related data collectively under a single name. An array is declared with a data type, name, and size. Elements are accessed via indexes that range from 0 to size-1. Common array operations include initialization, accessing elements using loops, input/output, and finding highest/lowest values. Arrays can be single-dimensional or multi-dimensional. Multi-dimensional arrays represent matrices and elements are accessed using multiple indexes. Common array applications include storing student marks, employee salaries, and matrix operations.