what does a nested loop mean code example

Example 1: nested loop

#include<stdio.h>

int main()
{
    int sum = 0, i, j;

    for(i = 0; i < 3; i++)
    {
        sum += i;
        for(j = 0; j < 3; j++)
        {
            sum += j;
            if(((i + j) % 2) == 1)
                break;
        }
    }

    printf("%d",sum);

    return 0;
}

Example 2: nested loop

int inner;
 string result = " "; 
 for (int outer = 0; outer < 3; outer++)
            {
                for (inner = 10; inner > 5; inner--)
                {
                    result += string.Format("Outer: {0} \tInner: {1} \n\n", outer,
                               inner);
                }
            } MessageBox.Show(result);
        }