| Abbreviation | Definition |
|---|---|
| FLEX | Fluorescence Explorer |
| FLM | Factor Label Method |
| FLP | Flowline Pressure |
| FM | Ferro-Magnetic |
| FM | Fluid Mechanics |
| FMCW | Frequency-Modulated Continuous Wave |
| FMFM | Fissile Mass Flow Monitor |
| FMI | Fast Moire Interferometry |
| FMPT | FERMI Machine Physics Team |
| fMRI | Functional magnetic resonance imaging |
| FMSF | Fissile Material Storage Facility |
| FMSS | Fast Mode Stationary Shock |
| FMSS | Fermi Mass Storage System |
| FMSS | Fermilab Mass Storage System |
| FMUP | Flawed Modern Ultramodern Physics |
| FNAL | Fermi National Accelerator Laboratory (Fermilab) |
| FND | Folded Normal Density |
| FNPB | Fundamental Neutron Physics Beamline |
| FOAM | Foam Optics And Mechanics |
| FOBP | Fundamentals of beam physics |