From Handbook for Student Academic Appointees
Graduate Fellowships are offered by departments, schools, or the University to selected graduate students. The stipends attached do not require specific duties and are excludable from taxable income to the extent they are actually used to pay for tuition and course-related books and expenses. All fellowship recipients must be enrolled full-time. A full-time course load is defined by each school, but may in no case be less than 6 credit hours per semester without special permission.