25 CFR §39.202

Homebound means a student who is educated outside the classroom. Home schooled means a student who is not enrolled in a school and is receiving educational services at home at the parent's or guardian's initiative. School day means a day as defined by the submitted school calendar, as long as annual instructional hours are as they are reflected in § 39.213, excluding passing time, lunch, recess, and breaks. Three-year average means:

(1) For academic programs, the average daily membership of the 3 years before the current year of operation; and

(2) For the residential programs, the count period membership of the 3 years before the current year of operation.