AASI stands for;

1AASIAmerican Association of Snowboard Instructors (affliated with Professional Ski Instructors of America)
2AASIAbel Assessment for Sexual Interest
3AASIAstronomical Association of Southern Illinois
4AASIAdvanced Aerodynamics and Structures, Inc. (aircraft manufacturer; Long Beach, CA)
5AASIAmbulatory Arterial Stiffness Index (blood pressure)
6AASIAssociate of the Ambulance Service Institute (UK)
7AASIAutomobile Association of South India
8AASIAdopt-a-School Initiative (Wake County Public School System; North Carolina)