A lengthy, but probably not exhaustive, list of things for which "IRA" stands:

Irish Republican Army        
Individual Retirement Account        
Individual Retirement Arrangement (IRS)        
International Reading Association        
Import Risk Analysis        
Individual Retirement Annuity (life insurance)        
Intercollegiate Rowing Association        
Indian Reorganization Act        
Internal Revenue Allotment (Philippines)        
Iran Air (ICAO code)        
Institut Régional d'Administration (French: Regional Institute of Administration)        
International Reference Alphabet (7-bit coded character set)        
Illinois Restaurant Association        
Interim Remedial Action        
Inherited Runs Allowed (baseball pitching statistic)        
Institut des Régions Arides (French: Institute of Arid Regions; Tunisia)        
Institute of Resource Assessment (Tanzania)        
Import Risk Assessment        
Ileorectal Anastomosis        
Independent Regulatory Agency        
Irregular Repeat-Accumulate (coding scheme)        
Indian Removal Act of 1830        
Illinois Recycling Association (formerly Illinois Association of Recycling Centers)        
Inventory Record Accuracy        
Integrated Risk Assessment        
Immediate Response Account        
Institut de Recherche Aérospatiale (French)        
Individualized Residential Alternative (New York)        
Investor Rights Agreement        
Institut de Radiophysique Appliquée        
Impulse Radiating Antenna        
Inverness Royal Academy        
Informal Rate Agreement        
Incubateur Régional d'Aquitaine (French: Aquitaine Regional Incubator; Aquitaine, France)        
Institut de Recherche Agronomique (Cameroon)        
Interim Removal Action        
Interim Response Action        
Independent Research Agency        
Institutional Research Award (NASA)        
Internet Routing Address        
Information Research Associates        
International Racing Association        
Intelligence Related Activity        
Independent Reporting Activity        
Information Requirement Analysis        
Indiana Rehabilitation Association        
Iterative Refinement Algorithm        
Interface Requirements Analysis        
Internal Revenue Association        
Intelligent Reuse Advisor (CASE)        
Intercon Research Associates        
Initial Request Analysis        
Inspection Régionale de l'Agriculture (French: Regional Agriculture Inspection; Senegal)        
International Roaming Agreement (telephone networks)        
Item and Release Application        
International Reiki Alliance        
Interrogation Réponse Aéronautique (French: Aeronautics Interrogation Response; Directorate of Civil Aviation; France)        
Information Retrieval for Advertising (workshop)        
Initial Risk Assessment        
Information Research and Analysis (University of North Texas; Denton, TX)        
Information Retrieval Agent        
Industrial Rope Access        
Individual Right of Action (legal claim)        
Inventoried Roadless Areas (various locations)        
Investor Relations Association        
Islamic Rating Agency (banking)        
Issue Resolution Agreement        
International Retrovirology Association        
International Regulatory Affairs Updates (est. 2004)