| Acronym | Definition |
|---|
| FOSS | Free and Open Source Software |
| FOSS | Future of Space Science |
| FOSS | Faculty of Social Science |
| FOSS | Free / Open-Source Software |
| FOSS | Full Option Science System |
| FOSS | Field Operations Support System |
| FOSS | Fiber-Optic Sensor System |
| FOSS | Field Operating Site Setup (US FEMA) |
| FOSS | Forum of Small States (UN) |
| FOSS | Follow-On System Stock |
| FOSS | Fiber Optics Sonar System |
| FOSS | Faculty Online Support Service |
| FOSS | Field Operated Support System (immigration database; Canada) |
| FOSS | Family Of System Study |
| FOSS | Federal Intelligence Security Service |