Grade 20 typically refers to a classification used in various contexts, such as education or materials. In education, it may indicate a specific level of achievement or a particular grade in a school system, often associated with students around the age of 15 or 16. In materials science, Grade 20 can refer to a type of steel or metal alloy, indicating its strength and composition. For example, Grade 20 steel is known for its durability and is often used in construction and manufacturing applications.