| Abbreviation | Definition |
|---|---|
| FIS | Friendly Information System |
| FISA | Foreign Intelligence Security Act |
| FISC | Fleet and Industrial Supply Center |
| FISH | Fighting In Someone's House |
| FISH | Friendly Instant Sympathetic Help |
| FISINT | Foreign Instrumentation Signals Intelligence |
| FISO | Force Integration Staff Officer |
| FISS | Foreign Intelligence and Security Services |
| FIST | Fire Support Team |
| FIST | Fleet Imagery Support Terminal |
| FIST | Fleet Initial Strike Team |
| FIST | Fleet Intelligence Support Team |
| FIST-DMD | FIST Digital Message Device |
| FISTV | Fire Support Team Vehicle |
| FIT | Field Interactive Training |
| FIT | First In Training |
| FIT | Flight In Training |
| FIT | Future Infantry Technologies |
| FITG | Fill In The Gap |
| FITG | Fort Indiantown Gap |