| Acronym | Definition |
|---|
| FDFI➣Fault Detection and Fault Isolation |
| FDFI➣First Day-First Issue (stamps) |
| FDFI➣Freunde des Flughafen Innsbruck (German: Friends of Innsbruck Airport; Innsbruck, Austria) |
| FDFI➣Fronteer Development Finance, Inc. (est. 1998; Delaware) |
| FDFI➣Flying Disc Federation of India |