Unsurprisingly, it is a way of averaging your grades (so that the whole of your academic career is compressed to one real number).
In the American system, the grades A,B,C,D,F are mapped to the numbers 4.0, 3.0, 2.0, 1.0, 0.0, respectively. Your GPA is a weighted average of your grades from 0.0-4.0
Thanks. I only commented because, well, there's a whole 95% of the world out there that won't know what a GPA is, and it'd be wonderful if region-specific stuff was kept out of submission comments. "Grades" is only three more characters than "GPA".
