An array is a set of numbers or data or items or things that are arranged in a specific manner like a sequence, list, two dimensional table, or 3 dimensional table. An array is a data structure to store data values in an ordered manner. The data members of an array are stored in the array or retrieved from the array using an index (which is an integer). An array has a fixed finite known size. The size of an array does not change. We may use all the memory space or leave some memory space unused in an array.
The elements or items or members or an array are stored generally in contiguous locations in memory or space. All the data items in an array are usually of the same kind or type. Each member of the array has the same characteristics or attributes, but may have a different value.
For example the sequence of natural numbers stored contiguous locations in memory can be treated as an array of natural numbers. A list of marks of students in an exam can be called an array.
One dimensional array is a simple sequence of data members of an array in one dimension only. So there is only one index required to store or retrieve the members of an array.