| Islamic Republic of Iran Academy of Sciences | Academic & Science |
| فرهنگستان علوم جمهوري اسلامي ايران | Academic & Science |
| Indian Archaeological Society | Academic & Science |
| Intelligent Assistant Systems | Academic & Science |
| Integral Ad Science | Academic & Science |
| Illinois Archaeological Survey | Academic & Science |
| Instrument Air Supply | Academic & Science |
| International Antiviral Society | Academic & Science |
| Industry Applications Society | Academic & Science |
| Académie Islamique des Sciences | Academic & Science |
| Interdisciplinary Arts and Sciences | Academic & Science |
| Académie Islamique des Sciences | Academic & Science |
| Islamic Academy of Sciences | Academic & Science |
| Academy of Sciences of the Islamic Republic of Iran | Academic & Science |
| International American School of Warsaw | Academic & Science |
| Institute of Agricultural Sciences | Academic & Science |
| Indiana Astronomical Society | Academic & Science |
| Institute for Advanced Study | Academic & Science |
| Indian Administrative Studies | Academic & Science |
| IEEE Industry Applications Society Annual Meeting | Academic & Science |
| International Accounting Standards | Accounts and Finance |
| International Accounting Standard | Accounts and Finance |
| Iasi | Airport Code |
| IEEE Industrial Applications Society | Associations & Organizations |
| Institute for Anarchist Studies | Associations & Organizations |
| Institut Aéronautique et Spatial | Associations & Organizations |
| Investment Analysts Society | Associations & Organizations |
| Immunisation Awareness Society | Associations & Organizations |
| Institute of the Aeronautical Sciences | Associations & Organizations |
| Iowa Archeological Society | Associations & Organizations |
| Iranian Arachnological Society | Associations & Organizations |
| Integrated Accounting Systems | Banking |
| Insolvency Advisory Service | Business |
| Installment Activities Statement | Business |
| International All Sports | Business |
| In-line Air Separator | Business |
| International Approval Services | Business |
| Insurance Accounting System | Business |
| International Association of Sufism | Business |
| Internationally Accepted Standard | Business |
| Innovative Aviation Services | Business |
| Integrated Asset Services | Business |
| Industrial Automation Solutions, Inc. | Business |
| Island Aviation Services, Limited | Business |
| Item Assembly Structure | Business |
| Inertial Active Suspension | Chemistry |
| Islam Awareness Series | Community |
| International Association of Sedimentologists | Community |
| International Association of Scientology | Community |
| Independent Art Structures | Community |
| Ideas, Action, and Success | Community |
| International AIDS Society | Community |
| Irish Association for Suicidology | Community |
| International Association of Scientologists | Community |
| Interdisciplinary Arts Symposium | Community |
| Industrial Applications Society (IEEE) | Computer and Networking |
| Insert After Sequence | Computer Assembly Language |
| Immediate Access Storage | Computer Hardware |
| Internet Authentication Service | Computing |
| Integrated Access Service | Computing |
| Image Acquisition System | Computing |
| Internet Access Server | Computing |
| Institute of Advanced Study | Computing |
| Integrated Access Server | Computing |
| Internet Web Application Server | Computing |
| Internet Acronym Server | Computing |
| Industrial Applications Society | Computing |
| Information Access Service | Computing |
| Interactive Application System | Computing |
| Intel Audio Studio | Computing |
| Intelligent Application Switching | Computing |
| Image Authentication System | Computing |
| i-Planet Application Server | Computing |
| Implementation Agreements | Computing |
| Intel Approved Supplier | Computing |
| Intel Attestation Service | Computing |
| Internet Analysis System | Computing |
| Internet Application Server | Computing |
| Internet Access Service | Computing |
| Internet Access System | Computing |
| Intergrated Automation System | Electronics |
| Initial Action Services | General |
| Independent Appeals Service | General |
| Individuals After Sarkar | General |
| Invasive Alien Species | General |
| Intermodulation Analysis System | General |
| Integrated Audio Systems | General |
| Integrated Access Switch | General |
| I Agree Sir | General |
| Industrial Automation Show | General |
| Integrated Archive Systems | General |
| International Accreditation Service | General |
| Immediate Access Store | General |
| Indian Administrative Services | General |
| Internal Airtightness System | General |
| Improvement of Agricultural Statistics | General |
| International Asset Systems | General |
| Individual Assignment System | General |
| Impact Assessment System | General |
| Inertia Active System | General |
| Integral Active Steering | General |
| Inlet Air Solenoid | General |
| International Auto Salon | General |
| Intersection Assistant System | General |
| International Auto Show | General |
| Instituto Ayrton Senna | General |
| Intelligent Access System | General |
| Inter Axle Shaft Angle | General |
| Intake Air System | General |
| Idle Air Stepper | General |
| Idle Air Solenoid | General |
| Indonesia Automotive Society | General |
| Italdesign Automobili Speciali | General |
| Introduction to Automobile Service | General |
| Indianapolis Auto Show | General |
| Instructional Assistants Seattletimes | General |
| Integrated Administrative System | General |
| Institute of Annoying Sillybillies | General |
| Integrated Analysis System | General |
| Intelligent Autonomous Systems | General |
| Institute of Alcohol Studies | Governmental |
| Internal Audit Service | Governmental |
| Institute for Advanced Studies | Governmental |
| Izquierda Asturiana | Governmental |
| Inmate Assignment System | Governmental |
| Institut d'Astrophysique Spatiale, France | Governmental |
| Integrated Acquisition System | Governmental |
| Indian Administrative System | Governmental |
| International Atherosclerosis Society | International |
| Internet Addiction Syndrome | Internet |
| Indian Academy of Sciences | Karnataka Government |
| Internal anal sphincter | Medical |
| International Aviculturists Society | Medical |
| Inter-Atrial Septum | Medical |
| I Am Sick | Messaging |
| Increased Attack Speed | Military and Defence |
| Intelligence Analysis System | Military and Defence |
| International Armaments Strategy | Military and Defence |
| Indian Administrative Service | Ministry of Personnel |
| Internet Authentication Server | Networking |
| Image Analysis & Stereology | News & Entertainment |
| Institute of African Studies | Regional |
| Independent African States | Regional |
| Interactive Advisory Software | Softwares |
| Inertial Active System | Space Science |
| Impact Assessment Sheet | Space Science |
| Indicated Airspeed | Space Science |
| Integrated Avionics System | Space Science |
| Indoor Action Sports | Sports |
| Iași International Airport | Transport & Travel |