| Acronym | Definition |
|---|
| PAI | Plasminogen Activator Inhibitor |
| PAI | Personal Accident Insurance |
| PAI | Population Action International |
| PAI | Piano Assetto Idrogeologico (Italian: Hydrogeological Plan) |
| PAI | Polyamide-Imide |
| PAI | P-Asserted Identity |
| PAI | Premise Attachment Interface |
| PAI | Pulse Accumulator Input |
| PAI | Personality Assessment Inventory |
| PAI | Pathogenicity Island |
| PAI | Protection and Advocacy Inc. |
| PAI | Project AI (Microsoft Flight Simulator) |
| PAI | Private Attorney Involvement (Legal Services Corporation) |
| PAI | Performing Arts Institute (various locations) |
| PAI | Pre-Approval Inspection (FDA) |
| PAI | Patient Assessment Instrument |
| PAI | Public Authority for Industry (Kuwait) |
| PAI | Publicly Available Information (valuation) |
| PAI | Parti Africain de l’Indépendance (African Independence Party; Burkina Faso) |
| PAI | Price Alignment Interest (finance) |
| PAI | Public Awareness Initiative (media) |
| PAI | Polymorphic Alu Insertion |
| PAI | Palo Alto Investors (Palo Alto, CA) |
| PAI | Party for African Independence (Burkina Faso) |
| PAI | Process After Input |
| PAI | Precision Aviation, Inc. (various locations) |
| PAI | Primary Aircraft Inventory |
| PAI | Peninsula Art Institute (California) |
| PAI | Puppetry Arts Institute (Independence, MO) |
| PAI | Performance Appraisal Instrument (employment) |
| PAI | Personnel Asset Inventory |
| PAI | Pesticide Active Ingredient |
| PAI | Product Authentication International (UK) |
| PAI | Pre Accession Instrument (EU) |
| PAI | Public Administration Institution (Washington Business and Technology Institute) |
| PAI | Processed Apples Institute |
| PAI | Pathology Associates International (SAIC subsidiary) |
| PAI | Permit Authorizing Individual (National Fire Protection Association) |
| PAI | Positive Action, Inc. (Twin Falls, ID; education) |
| PAI | Pure Active Ingredient (EPA) |
| PAI | Performance Audit Inspection |
| PAI | Polizia dell'Africa Italiana (Italian African Police) |
| PAI | Panduit Authorized Installer |
| PAI | Pancreatitis Association International |
| PAI | Prescient Applied Intelligence (Park City, UT) |
| PAI | pubic arch interference |
| PAI | Pre-Arrival Instruction (emergency dispatch) |
| PAI | Physicians Advocacy Institute, Inc. |
| PAI | Programme d'Action Intégré (French: Integrated Action Program) |
| PAI | Physics Applications, Inc. |
| PAI | Pacific Achievement International |
| PAI | Principal Arterial-Interstate |
| PAI | Passengers Association of India |
| PAI | Poverty Alleviation Initiative |
| PAI | Payload Analytical Integration |
| PAI | Programme d’actions intégrées de recherche (Research Integrated Action Programmes) |
| PAI | Princeton AIDS Initiative (Princeton, NJ) |
| PAI | Personal Appearance Inspection (USAF Academy) |
| PAI | Pervasive Artificial Intelligence |
| PAI | Product Acquisition and Installation |
| PAI | Police Accident Investigator |
| PAI | Plan d'Action Incendie (French: Fire Action Plan) |