Yours, Etc.: Origins and Uses of 8 Sign-Offs
an elementary or secondary school in which the instructional program is divided into school years, known as grades or forms. At the end of each academic year, pupils move from one grade to the next higher in a group, with only an occasional outstanding achiever allowed to "skip" a grade, or advance beyond his fellows to a still higher grade. The practice of grading began in Germany as early as the 16th century and thence spread worldwide.