| Acronym | Definition |
|---|
| GSI | Gesellschaft für Schwerionenforschung (German Federal Research Institute f |
| GSI | General Steel Holdings, Inc. (Beijing, China) |
| GSI | Geographical Survey Institute (Ibaraki, Japan) |
| GSI | Global Security Institute |
| GSI | Government Secure Intranet |
| GSI | Geological Survey of India |
| GSI | Genuine Software Initiative (Microsoft) |
| GSI | Graduate Student Instructor |
| GSI | Gonadosomatic Index |
| GSI | Global Severity Index |
| GSI | Government Source Inspection |
| GSI | Get Someone In |
| GSI | Gross Sexual Imposition |
| GSI | Gross Scheduled Income |
| GSI | Geological Strength Index |
| GSI | Global Single Instance (Oracle) |
| GSI | Giga-Scale Integration |
| GSI | GameSpy Industries |
| GSI | Generic Safety Issue |
| GSI | Geological Survey Institute (Japan) |
| GSI | Gerontological Services, Inc. (Santa Monica, CA) |
| GSI | Glide Slope Indicator |
| GSI | Global System Interrupt |
| GSI | Grid Security Interface |
| GSI | Government Systems Incorporated |
| GSI | Global Strike Integration (USSTRATCOM Joint Functional Component Command-US DoD) |
| GSI | Geriatrics-For-Specialists Initiative |
| GSI | Genie Scientific, Inc. (manufacturer of lab fume hoods and metal cabinets) |
| GSI | Geo Services International Ltd (UK) |
| GSI | Goal Systems International (Port Angeles, WA) |
| GSI | Generic Software Interface |
| GSI | Goddard Safety Initiative |
| GSI | Guest Service Interaction |
| GSI | Ground Safety Instruction |
| GSI | Graham Studios Inc (Philadelphia, Pennsylvania) |
| GSI | Gulf States Initiatives |
| GSI | GoodSeed International |
| GSI | GPETE Support Item |
| GSI | Globecomm Systems International (contractor) |
| GSI | Gerencia de Seguridad Institucional (Guatemala) |
| GSI | Generator Services International, Inc. |