What is the difference between GROUP BY and ORDER

What is the difference between GROUP BY and ORDER BY in MySQL?

ORDER BY [col1],[col2],…,[coln];
Tells DBMS according to what columns it should sort the result. If two rows will have the same value in col1 it will try to sort them according to col2 and so on.

GROUP BY [col1],[col2],…,[coln];
Tells DBMS to group results with same value of column col1. You can use COUNT(col1), SUM(col1), AVG(col1) with it, if you want to count all items in group, sum all values or view average.