grade

They also appointed and removed, at their own pleasure,
teachers of every grade. --Buckle.
[1913 Webster]

2. In a railroad or highway: (a) The rate of ascent or descent; gradient; deviation
from a level surface to an inclined plane; -- usually
stated as so many feet per mile, or as one foot rise
or fall in so many of horizontal distance; as, a heavy
grade; a grade of twenty feet per mile, or of 1 in
264.
(b) A graded ascending, descending, or level portion of a
road; a gradient.
[1913 Webster]

3. (Stock Breeding) The result of crossing a native stock with some better breed. If the crossbreed have more than
three fourths of the better blood, it is called high
grade.
[1913 Webster]

At grade, on the same level; -- said of the crossing of a railroad with another railroad or a highway, when they are
on the same level at the point of crossing.

Down grade, a descent, as on a graded railroad.

Up grade, an ascent, as on a graded railroad.

Equating for grades. See under Equate.

Grade crossing, a crossing at grade. [1913 Webster]

Grade Grade, v. t. [imp. & p. p. Graded; p. pr. & vb. n. {Grading}.]
1. To arrange in order, steps, or degrees, according to size,
quality, rank, etc.
[1913 Webster]

2. To reduce to a level, or to an evenly progressive ascent, as the line of a canal or road.
[1913 Webster]

3. (Stock Breeding) To cross with some better breed; to improve the blood of.
[1913 Webster]

Source: The Collaborative International Dictionary of English