The term HIGH SCHOOL CLASS, FOR SHORT can be summarized by three crossword solutions: BIO (3 letters), SEXED (5 letters), and PHYSED (6 letters). BIO stands for Biology, a science class typically taken in high school. SEXED stands for Sex Education, a course that is often part of the high school curriculum. PHYSED stands for Physical Education, another class commonly taken in high school. All three of these classes are usually abbreviated when referring to them as part of a high school class.