A session is a one off workout session, also called a casual session. For example: one Personal Training session, one Massage session; one (1hr) Boot camp session; one (1hr) Boxercise session.
A program is a 10 weeks indoor fitness program. People sign up for the program to be assured of their place in their specific and preferred class(es) and to benefit from the discounted program fee.
A program term is always in line with the school terms and is over 10 weeks.