Jagged Arrays

    A jagged array is an array whose elements are arrays. The elements of a jagged array can be of different dimensions and sizes. A jagged array is sometimes called an "array of arrays." The following examples show how to declare, initialize, and access jagged arrays.

A jagged array is an array of arrays, and therefore its elements are reference types and are initialized to null.
int[][] jaggedArray = new int[3][];
Before you can use jaggedArray, its elements must be initialized. You can initialize the elements like this:
jaggedArray[0] = new int[5];
jaggedArray[1] = new int[4];
jaggedArray[2] = new int[2];

MSDN Link:http://msdn.microsoft.com/en-us/library/2s05feca.aspx