| Acronym | Definition |
|---|
| RAI | Royal Anthropological Institute |
| RAI | Resident Assessment Instrument |
| RAI | Radio Televisione Italiana |
| RAI | Radioactive Iodine |
| RAI | Reynolds American Inc. |
| RAI | Return As Is |
| RAI | Robotics and Artificial Intelligence (various organizations) |
| RAI | Remote Alarm Indication |
| RAI | Rapid Application Integration |
| RAI | Resource Availability Indication |
| RAI | Remote Assistance Initiation |
| RAI | Routing Area Identity |
| RAI | Rico Auto Industries (India) |
| RAI | Request for Additional Information |
| RAI | Raised Air Intake (vehicles) |
| RAI | Reliability Assurance Initiative (North American Electric Reliability Corporation) |
| RAI | Ridgewood Art Institute (New Jersey) |
| RAI | Radar Altimeter Indicator (avionics) |
| RAI | Radio Audizioni Italiane |
| RAI | Robert Allen Institute (Provo, UT) |
| RAI | Recherche d'Agglutinines Irrégulières (French: Irregular Agglutinins Search) |
| RAI | Research Activity Index (various schools) |
| RAI | Registro de Aceptaciones Impagadas (Spanish) |
| RAI | Registro Aeronautico Italiano (Italian Aircraft Registry) |
| RAI | Resource Associates International (Spokane, WA) |
| RAI | Risk Appetite Indicator (investing) |
| RAI | Resource Availability Indicator (H.323 gateways) |
| RAI | Routing Area Identification |
| RAI | Random Access Iterator (computer programming) |
| RAI | Republicans Abroad International |
| RAI | Respiratory Arousal Index |
| RAI | Research Institute for Aquaculture (Vietnam) |
| RAI | Resultados Antes de Impostos (Portuguese: results before taxes) |
| RAI | Regional Airspace Initiative |
| RAI | Resource Adapter Interface |
| RAI | Rural Alliance Inc (Shasta, CA) |
| RAI | Rural Access Initiative |
| RAI | Rules as Interpreted (gaming) |
| RAI | Rah Ahane Iran (Iranian Railways) |
| RAI | Radio and Allied Industries |
| RAI | Request Arrival Interval |
| RAI | Rural Area Interface |
| RAI | Rangeless Airborne Instrumentation |
| RAI | Research Access Incorporated |
| RAI | Required Approach Interval (aviation) |
| RAI | Recruit Alliance India (Hyderabad, India recruitment firm) |
| RAI | Reconnaissance Attack Interface |
| RAI | Readiness Assessment Instrument (various applications) |
| RAI | Remote Altitude Indicator |
| RAI | Random Access & Inquiry |
| RAI | Reading and Arithmetic Indexes |