| Abbreviation | Definition |
|---|---|
| FER | Force Exchange Ratio |
| FER | Fractional Exchange Ratio |
| FES | Foreign Elite Soldier |
| FESO | Field and Emergency Support Office |
| FESR | Far East Strategic Reserve |
| FEST | Forward Engineer Support Team |
| FET | Facility Engineer Team |
| FET | Follow-on Equipment Training |
| FEU | Forty-Foot Equivalent Unit |
| FEWC | Fleet Electronic Warfare Center |
| FEZ | Fighter Engagement Zone |
| FF | Fast Frigate |
| Ff | Fatigue Correction Factor |
| FF | Fire Finder |
| FF | Fist Fight |
| FF | Freeboard Forward |
| FF | Freedom Fighter |
| FF | Friendly Fire |
| FF | Navy Fast Frigate |
| FFA | Free-Fire Area |