| International Schools Services | Academic & Science |
| Inertial Surveying System | Academic & Science |
| Iron and Steel Society | Academic & Science |
| انجمن آمار ايران | Academic & Science |
| International Superyacht Society | Academic & Science |
| International Society of Surgery | Academic & Science |
| International Social Service | Academic & Science |
| International Student Services | Academic & Science |
| International Students and Scholars | Academic & Science |
| Instructional Support Staff | Academic & Science |
| International Students Service | Academic & Science |
| Introduction to Social Sciences | Academic & Science |
| Institute of Social Studies | Academic & Science |
| Integrative Studies in Social Sciences | Academic & Science |
| Ion Scattering Spectrometry | Academic & Science |
| Indian Springs School | Academic & Science |
| Ion Scattering Spectroscopy | Academic & Science |
| Integrated Sounding System | Academic & Science |
| Inclination Sensor System | Academic & Science |
| A Industrial Social Sciences | Academic & Science |
| Wiscasset (me) | Airport Code |
| Cleaning service | Business |
| Information Systems and Services | Business |
| Institutional Shareholder Services | Business |
| Important Slam Shooter | Business |
| Instrument Sales and Service | Business |
| Integrated Support Service | Business |
| ISS Group, LTD. | Business |
| Infoseek Software Systems | Business |
| Infantile Seizure Society | Business |
| Iron & Steel Society | Business |
| Iranian Statistical Society | Business |
| In Service Support | Business Management |
| Industry Strategy Symposium | Community |
| International Switching Symposium | Community |
| Imprinted Sportswear Show | Community |
| International Sabre Symposium | Community |
| Indiana Science Standards | Community |
| In-School Suspension | Community |
| Iredell Statesville Schools | Community |
| International School of Samui | Community |
| Independent Schools Section | Community |
| Inter-Satellite Service | Computer and Networking |
| Inhibit Symmetrical Swapping | Computer Assembly Language |
| Internet Security System | Computing |
| Information Security Standard | Computing |
| Internal Security Service | Computing |
| International Security Standards | Computing |
| Internet Security Systems | Computing |
| Institute of security studies | Computing |
| Industry Standard Server | Computing |
| Income Support Supplement | Computing |
| Image Server System | Computing |
| Inno Setup Script | Computing |
| Index Search System | Computing |
| Inhibit Symmetric Swapping | Computing |
| Intel Solutions Summit | Computing |
| Image Sensor Solutions | Computing |
| Intel Speed Step | Computing |
| Inactive Shadow Set | Computing |
| Image Symbol Set | Computing |
| Industry Standard Servers | Computing |
| Intelligent Storage System | Computing |
| Integrated Storage Solution | Computing |
| Integrated Switching System | Computing |
| Internet Security Specialist | Computing |
| Intel Select Solutions | Computing |
| Instruction Set Simulator | Computing |
| Ion Scattering Spectrometry/spectroscopy | Electronics |
| Imperial Star Ship | General |
| Interactive Session Support | General |
| Identical Screening Search | General |
| Imprinted Sportswear Shows | General |
| Incremental Spatial Search | General |
| Information Support System | General |
| Information Systems Services | General |
| Irradiation Side Sampling | General |
| Independent Studio Services | General |
| Indestructible Space Sperm | General |
| International Space Station is | General |
| Inner Shell Spectroscopy | General |
| Instructional Support Services | General |
| Integrated Sounding Systems | General |
| Integrative Studies in Social | General |
| Intl Space Station | General |
| Integrated Sealing Systems | General |
| Independent Service Set | General |
| Interactive Surfaces and Spaces | General |
| Inside Self Storage | General |
| Industrial Security System | General |
| Integrated Seaming System | General |
| Idea Star Singer | General |
| Intelligent Safety Shield | General |
| Impala Ss | General |
| Italian Spaghetti Sauce | General |
| Institute of Silly Strings | General |
| Impotent Sea Snakes | General |
| Instant Space Station | General |
| Internal Stupidity Society | General |
| Inside Skin Surface | General |
| Integrated Sealing System | General |
| I Should Sleep | General |
| Integrated Surveillance System | General |
| Input Shaft Speed | General |
| Intermediate Steering Shaft | General |
| Integrated Safety Systems | General |
| Instant Start System | General |
| Idle Stop Start | General |
| Intelligent Safety System | General |
| Integrated Service Systems | General |
| Intelligent Stop Start | General |
| Idle Stop Solenoid | General |
| Idle Stop System | General |
| International Superstars Series | General |
| Imaging Science Subsystem | General |
| Intelligence Systems Secretariat | Governmental |
| Immigrant Social Services | Governmental |
| Indices Search Slip | Governmental |
| Integrated Summary of Safety | Governmental |
| Institute for Security Studies | Governmental |
| Institute for Standardization of Serbia | Governmental |
| Imposition of Sentence Suspended | Governmental |
| Inhibit/override Summary Snapshot | Governmental |
| International Seating Symposium | International |
| Internet Security Service | Internet |
| Inpatient Services Specialist | Medical |
| I Said So | Messaging |
| Intelligent Security Systems | Messaging |
| Inspection Selection System | Military and Defence |
| Injury Severity Score | Military and Defence |
| Integrated Systems Support | Military and Defence |
| Interactive Survivability Simulation | Military and Defence |
| In-system Select | Military and Defence |
| Internet Server Supplement | Networking |
| Initial Send Sequence | Networking |
| Input To State Stability | Physics Related |
| Intelligent Software Solutions | Softwares |
| International Space Station | Space Science |
| Inertial Subsystem | Space Science |
| Inhibit/override Summary Snapshot Display | Space Science |
| Installation Support Services | Space Science |
| Instruction Summary Sheet | Space Science |
| Integrated Support Stand | Space Science |
| Integrated System Schematic | Space Science |
| Iris (italian Research Interim Stage) Spinning Stage | Space Science |
| Improving Soccer Sportsmanship | Sports |
| International Superstar Soccer | Sports |
| Instructional Sports Skills | Sports |
| Wiscasset Airport | Transport & Travel |
