| Acronym | Meaning |
| FUSE | Far Ultraviolet Spectroscopic Explorer |
| FUSRAP | Formerly Utilized Sites Remedial Action Program (radioactive Materials Related) |
| FV-CAS-SCF | Full Valence-complete Active Space-SCF |
| FV-MC-SCF | Full Valence Multiconfiguration Self-consistent Field |
| FVC | Forced Vital Capacity (lung Function) |
| FVEH | Fragment Valence Effective Hamiltonian (in Electronic-structure Calcns. On Mol. Fragments) |
| FVP | Flash Vacuum Pyrolysis |
| FVRCI | Full Valence Rydberg Configuration Interaction |
| FVVM | Finite Volume Variational Method (for Mol. Calcns.) |
| FWA | Fluorescent Whitening Agent |
| FWE | Faddeev-Watson Expansion (for T-operator In Atomic Collisions) |
| FWHH | Full Width At The Half-height |
| FWHM | Full Width At Half Maximum |
| FWHP | Full Width At Half Peak |
| FWM | Four-wave Mixing |
| FWPCA | Federal Water Pollution Control Act Of 1972 |
| FWPCA | Federal Water Pollution Control Administration |
| FXR | Farnesoid X Receptor |
| FY | Fiscal Year |
| FYNES | Fluorescence Yield Near Edge Spectroscopy |
| FZ | Fusion Zone |
| FZP | Fresnel Zone Plate |
| G-CSF | Granulocyte Colony-stimulating Factor |
| G.P. | Guinier-Preston Zone |
| G1 | Gaussian-one (theory For Calcg. Mol. Energies) |
| G2 | Gaussian-two (an Ab Initio Mo Theory For Mol. Energies Calcn.) |
| G6PD | Glucose-6-phosphate Dehydrogenase |
| GA | Glauber Approximation (in Electron-atom Scattering) |
| GA | Genetic Algorithm |
| GABA | Gamma-aminobutyric Acid |
| GAC | Granular Activated Carbon |
| GACT | Generally Available Control Technology |
| GACT | Granular Activated Carbon Treatment |
| GAD | Glutamic Acid Decarboxylase |
| GADD | Growth Arrest And DNA Damage |
| GAEP | Generalized Atomic Effective Potential |
| GAGE | Global Atmospheric Gases Experiment |
| GAGP | Generalized Antisymmetrized Geminal Power (wave Function) |
| GAIIA | Global Alliance Of Information Industry Associations |
| GAIM | Global Analysis Interpretation And Modeling |
| GAIN | Global Agricultural Information Network |
| GALE | Genesis Of Atlantic Lows Experiment |
| GALEX | Galaxy Evolution Explorer |
| GALP | Good Automated Laboratory Practices |
| GALT | Gut-associated Lymphoid Tissue |
| GAM | Generalized Additive Model |
| GAMESS | General Atomic And Molecular Electronic Structure System |
| GAMETAG | Global Atmospheric Measurements Experiment Of Tropospheric Aerosols And Gases |
| GAMOT | Global Acoustic Mapping Of Ocean Climate |
| GAMP | Global Atmospheric Measurements Program |