The meaning of GRADE is a level of study in an elementary, middle, or secondary school that is completed by a student during one year. How to use grade in a sentence. GRADE definition: 1. a level of quality, size, importance, etc.: 2. a number or letter that shows how good someone's…. Learn more. In the United States, a grade is a group of classes in which all the children are of a similar age. When you are six years old you go into the first grade and you leave school after the twelfth grade. 1. a position or degree in a scale, as of quality, rank, size, or progression: small-grade eggs; high-grade timber. Definition of grade noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.