(grād) noun
1. A degree or step in any scale, as of quality, ability, dignity, etc.
2. A group of persons of the same rank or station: all grades of society.
3. Rate or rank in the U.S. armed forces. See page 548.
4. A class of things of the same quality or value: a high grade of wool.
5. U.S. a One of the divisions of an elementary or secondary school covering a year of work. b The pupils in such a division.
6. plural U.S. A grade school.
7. A scholastic rating or mark on an examination or in a course.
8. A part of a road, track, or surface inclined to the horizontal.
9. The degree of inclination of a road or the like as compared with the horizontal.
10. Agric. An animal (as a cow or sheep) or a class of animals produced by crossing a common or other breed with a pure or better breed.
—at grade At the same point of grade or inclination: a road crossing another at grade.
—v. grad·ed, grad·ing v.t.
1. To arrange or classify by grades or degrees, according to size or quality.
2. To assign a grade to.
3. To gradate.
4. To make level or properly inclined: to grade a road.
5. To improve by crossbreeding with better stock: often with up: to grade up a herd of cattle.
—v.i.
6. To take rank; be of a grade. [<F <L gradus step]
—grad′er noun

Zool.
Manner of walking: plantigrade. [<L gradi walk]