| Acronym | Meaning |
| FACS | Fluorescence Atom-coincidence Spectroscopy |
| FACS | Fluorescence-activated Cell Sorting |
| FACSS | Federation Of Analytical Chemistry And Spectroscopy Societies |
| FACT | Facility For The Analysis Of Chemical Thermodynamics |
| FACT | Fuel And Combustion Technology |
| FACTS | Facilities And Company Tracking System |
| FAD | Failure Assessment Diagram |
| FAD | Flavin Adenine Dinucleotide |
| FADD | Fas-associated Death Domain Protein |
| FADEC | Full Authority Digital Engine Control |
| FAEC | Factor Analysis With Equilibrium Constraints |
| FAES | Flame Atomic Emission Spectroscopy |
| FAFS | Flame Atomic Fluorescence Spectroscopy |
| FAGE | Fluorescence Assay With Gas Expansion |
| FAGS | Federation Of Astronomical And Geophysical Services |
| FAIMS | High-field Asymmetric Waveform Ion Mobility Spectrometry |
| FAK | Focal Adhesion Kinase |
| FAKE | Fast Accurate Kinetic-energy (MO Method) |
| FALS | Familial Amyotrophic Lateral Sclerosis |
| FAM | Friable Asbestos-containing Material |
| FAMA | Fluorescent Antibody Membrane Antigen |
| FAME | Fatty Acid Methyl Ester |
| FAMOS | Floating-gate Avalanche-injection Metal-oxide Semiconductor |
| FAMOUS | French-American Mid-Ocean Undersea Study |
| FANES | Furnace Atomization Non-thermal Emission Spectrometry |
| FAO | Food And Agriculture Organization |
| FAO | Floating Atomic Orbital |
| FAO | Frozen Atomic Orbital |
| FAOS | Fluorescent Activated Organelle Sorting |
| FAP | Familial Adenomatous Polyposis |
| FAP | Familial Amyloidotic Polyneuropathy |
| FAPAS | Food Analysis Performance Assessment Scheme |
| FAPES | Furnace Atomization Plasma Emission Spectrometry |
| FAPS | Field-effect-addressable Potentiometric Sensor |
| FAR | Federal Acquisitions Regulations |
| FARCE | Freezing At Reactive Centers Of Enzymes |
| FARM | Fixed-angle Reactor Model (in Quantum Calcns. On Reactive Scattering) |
| FAS | Federation Of American Scientists |
| FAS | Fatty Alcohol Sulfates (surfactants) |
| FAS | Flame Absorption Spectroscopy |
| FASEB | Federation Of American Societies For Experimental Biology |
| FASI | Field-amplified Sample Injection |
| FASS | Field-amplified Sample Stacking |
| FASSST | FAst Scan Submillimeter Spectroscopy Technique |
| FASST | Fast Scan Submillimeter Spectroscopic Technique |
| FAST | Fast Atom Sample Tester |
| FAST | Fugitive Assessment Sampling Train |
| FAST | Forward Alpha Scattering Technique |
| FASTER | FAst Spinning Gives Transfer Enhancement At Rotary Resonance |
| FASTMAP | Fast Automatic Shimming Technique By Mapping Along Projections |