Meaning of “grade” - Learner’s Dictionary

grade

noun [ C ] uk us /ɡreɪd/
SCORE

B1 a number or letter that shows how good someone's work or performance is:

Steve never studies, but he always gets good grades.
UK Carla got a grade A in German.
LEVEL

B2 a level of quality, size, importance, etc:

I applied for a position a grade higher than my current job.
SCHOOL GROUP US

a school class or group of classes for students of the same age or ability:

My son is in fifth grade.

(Definition of “grade noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)