Primary Aircraft Inventory 
Personal Accident Insurance 
plasminogen activator inhibitor 
PRODUCT ASSURANCE INSTRUCTION 
Programmer Appraisal Instrument 
Payload Analytical Integration 
Performance Audit Inspection 
Personality Assessment Inventory 
Pesticide Active Ingredient 
Pre-approval inspection 
Privacy Act Information 
Procurement Automation Institute 
Protocol Addressing Information 
PA inhibitor 
PA inhibitors 
Pacific American Income Shares, Inc. 
Paradise Airways 
Parallel Artificial Intelligence 
participation index 
Passive Acquired Immunity 
pathogenicity island 
pathogenicity islands 
Patient Assessment Instrument 
percentage area of immunoreactivity 
percutaneous acetic acid injection 
percutaneous alcohol injection 
periapical index 
Periodic Annual Increment 
Personnel Accrediation Institute 
physical activity index