WordNet sense 1 (a relative position or degree of value in a graded group):

level, tier, tier

WordNet sense 2 (one-hundredth of a right angle):

grad

WordNet sense 3 (a body of students who are taught together):

class, form

WordNet sense 4 (a degree of ablaut):

gradation

WordNet sense 5 (a number or letter indicating quality (especially of a student's performance)):

mark, score

WordNet sense 6 (the height of the ground on which something stands):

ground level

WordNet sense 7 (a position on a scale of intensity or amount or quality):

degree

WordNet sense 8 (assign a rank or rating to):

order, place, range, rank, rate