| FIM | Field Instruction Memorandum | In English | |
| FIMS | Framework for Integrated Manufacturing System | In English | → Engineering, technology |
| FINA | Fédération Internationale de Natation | In English | → Organizations and associations → Sport, physical exercises |
| FinLAS | Finnish Laboratory Animal Scientists | In English | → Organizations and associations → Biological sciences → Medicine |
| FIO | Furnished and Installed By Others | In English | |
| FIOpt | Fiber Integrated Optics | In English | → Serial publications, periodicals → Optics → Telecommunications |
| FIPA | Foreign Investment Promotion Agency | In English | → 33972 |
| FIPS | Federal Information Processing Standard | In English | → Computer-based techniques → Standardization |
| FIR | Fuel Indicator Reading | In English | → Vehicle engineering |
| FIRSSE | Far Infrared Sky Survey Experiment | In English | → Astronomy → Spaceflight engineering, astronautics |
| FIS | Facility Interface Sheet | In English | |
| FISA | Facility Inspection Shakedown Acceptance | In English | |
| FISB | Foreign Investment Services Bureau | In English | → 33972 |
| FISH | Fluorescence In Situ Hybridization | In English | → 5708 |
| FIST | Final Integrated System Test | In English | |
| FIST | Functional Integrated System Test | In English | |
| FIT | Fault Isolation Test | In English | |
| FITB | Fiji Islands Trade & Investment Board | In English | → 33972 |
| FITCO | Fuel International Trading Corporation | In English | → Energy economics |
| FITS | Flexible Image Transport System | In English | |
| FIV | Feline Immunodeficiency Virus | In English | → Virology → Immunology and allergy → Veterinary medicine |
| FIV | Fuel Isolation Valve | In English | → Vehicle engineering |
| FKB | Flight Display Keyboard | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FL | Forward Link | In English | |
| FL | Feed Line | In English | |
| FL | Flow Line | In English | |
| FLAG | Flexible Assignment Generator | In English | |
| FLAGE | Flexible Lightweight Agile Guided Experiment | In English | |
| FLAIR | Functional Language Articulated Interactive Resource | In English | |
| FLAPS | Flight Application Software | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics → Software |
| FLC | Federal Library Committee | In English | → Libraries |
| FLC | Forward Load Control | In English | |
| FLCA | Forward Load Controller Assembly | In English | |
| FlDy | Fluid Dynamics | In English | → Serial publications, periodicals → 5325 |
| FlDyR | Fluid Dynamics Research | In English | → Serial publications, periodicals → 5325 |
| FlDyT | Fluid Dynamics Transactions | In English | → Serial publications, periodicals → 5325 |
| FliIn | Flight International | In English | → Serial publications, periodicals → Aeronautics, aircraft |
| FLIM | Fluorescence Lifetime Imaging | In English | |
| FLIR | Forward-Looking Infrared | In English | |
| FLLK | Frustum-Lifting Lug Kit | In English | |
| FlMSR | Fluid Mechanics Soviet Research | In English | → Serial publications, periodicals → 532 |
| FLOPS | Floating-Point Operations Per Second | In English | → Computer science |
| FLOSS | Free/Libre Open Source Software | In English | → Software |
| FLPS | Flight Load Planning System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FLR | Flight Log Recorder | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FLRSL | Flag Research Centre of Sri Lanka | In English | → Organizations and associations → 9299 |
| FLSA | Fair Labor Standards Act | In English | |
| FLSC | Flexible Linear-Shaped Charge | In English | |
| FluQ | Fluids Quarterly | In English | → Serial publications, periodicals → 532 |
| FM | Fluid Module | In English | |
| FM | Frequency Modulation | In English | → Telecommunications |
| FM | First Mold | In English | |
| FM | Flight Model | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FM | Fracture Mechanics | In English | → Physics |
| FM | Frequency Modulated | In English | → Telecommunications |
| FM/CW | Frequency-Modulated Continuous Wave | In English | → Telecommunications |
| FM/FM | Frequency Modulation/Frequency & Multiplexing | In English | → Telecommunications |
| FM/PM | Frequency Modulation/Phase Modulation | In English | → Telecommunications |
| FMA | Failure Mode Analysis | In English | |
| FMA | Finnish Medical Association = SLL | Suomen Lääkäriliitto | In Finnish = FLF | Finlands Läkarförbundet | In Swedish |
In English | → Associations → Medicine |
| FMAD | Fluid Management and Distribution | In English | |
| FMAG | Fluid Mechanics of Astrophysics and Geophysics | In English | → Serial publications, periodicals → Astronomy → 532 → Geophysics |
| FMAHTS | Flight Manifest and Hardware Tracking System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics → Hardware |
| FMAR | Final Mission Analysis Review | In English | |
| FMC | Forward Motor Controller | In English | → Vehicle engineering |
| FMC | Fresenius Medical Care | In English | → Medicine |
| FMC | Franciscan Missionaries of Saint Clare | In English | → Roman catholic church |
| FMCA | Forward Motor Controller Assembly | In English | → Vehicle engineering |
| FMCF | First Manned Captive Flight | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FMCS | Federal Mediation and Conciliation Services | In English | → Public administration, government |
| FMCSA | Federal Motor Carrier Safety Administration (www.fmcsa.dot.gov) | In English | → Central administration → Vehicle engineering |
| FMD | Fixed-Module Drive | In English | |
| FMD | Foot-and-Mouth Disease | In English | → Veterinary medicine |
| FMD&C | Flight Mechanics, Dynamics, and Control | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FMDM | Flexible Multiplexer/Demultiplexer | In English | |
| FMEA | Failure Mode and Effects Analysis | In English | |
| FMEC | Forward Master Events Controller | In English | |
| FMECA | Failure Modes and Effects Criticality Analysis | In English | |
| FMI | Finnish Meteorological Institute | In English | → Meteorology, climatology |
| FMK | Field Modification Kit | In English | |
| FML | Fault Message Line | In English | |
| FML | Final Materials List | In English | |
| FMM | Franciscan Missionaries of Mary | In English | → Roman catholic church |
| FMM | Free Media Movement | In English | → Organizations and associations → Newspapers, journalism |
| FMNR | First Nations and Métis Relations | In English | |
| FMO | Flight Medical Officer | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics → Medicine |
| FMOF | First Manned Operational Flight | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FMOF | First Manned Orbital Flight | In English | → Spaceflight engineering, astronautics |
| FMOFEV | First Manned Orbital Flight With EVA | In English | → Spaceflight engineering, astronautics |
| FMOFPL | First Manned Orbital Flight With Payload | In English | → Spaceflight engineering, astronautics |
| FMP | Facility Management Plan | In English | |
| FMPAC | Fixed Multipurpose Application Console | In English | |
| FMR | Field Modification Request | In English | |
| FMR | Function Max Rate | In English | → Mathematics |
| FMR | Forced Migration Review | In English | → Serial publications, periodicals → Migrations |
| fMRI | Functional Magnetic Resonance Imaging | In English | → Nuclear, atomic, and molecular physics → Diagnostics |
| FMS | Food Management Subsystem | In English | → Food technology |
| FMS | Forms Management System | In English | |
| FMS | Functional Master Schedule | In English | |
| FMS | Fluid Management System | In English | |
| FMSP | Frequency Modulation Signal Processor | In English | → Telecommunications |
| FMT | Flight Management Team | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FMW | Fair Market Value | In English | → Finance |
| FMX | Frequency Modulation Transmitter | In English | → Telecommunications |
| FNAS | Faculty of Natural and Agricultural Sciences | In English | → Higher education, universities → Biological sciences → Botany → Agricultural sciences |
| FNAS | Fidelity National Agency Solutions | In English | → Insurance |
| FND | Facility Need Date | In English | |
| FNL | Fluctuation and Noise Letters | In English | → Serial publications, periodicals → Acoustics |
| FNOC | Fleet Numeric Oceanography Center | In English | → Marine research, oceanography |
| FNT | Failure Notification Telex | In English | → Telecommunications |
| FO | Functional Objective | In English | → Management |
| FO | Fiber-Optic | In English | → Telecommunications |
| FOAF | Friend of a Friend | In English | → Programming languages → Networks, communication |
| FOB | Fractional Orbit Bombardment | In English | → Spaceflight engineering, astronautics → Military engineering |
| FOB | Flight Operations Building | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOBS | Fractional Orbit Bombing System | In English | → Spaceflight engineering, astronautics → Military engineering |
| FOC | Full Operational Capability | In English | |
| FOC | Fleet Operational Capability | In English | → Aeronautics, aircraft |
| FOC | Faint Object Camera | In English | |
| FOCR | Final Operational Concept Review | In English | |
| FOCUS | ReinFOrcing CompUter Science | In English | → Computer science |
| FOD | Flight Operations Directorate | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FODM | Field Operations Data Model | In English | → Software |
| FODM | Friends of Dukes Meadows | In English | → Organizations and associations |
| FODM | Friends of Dyke Mar | In English | → Organizations and associations → Nature |
| FODS | Fiber-Optic Demonstration System | In English | → Telecommunications |
| FOE | Flight Operations Engineer | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOE | Friends of the Earth | In English | → Organizations and associations |
| FOF | First Orbital Flight | In English | → Spaceflight engineering, astronautics |
| FOF | Flight Operations Facility | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOF | First Operational Flight | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOG | Fiber-Optic Gyro | In English | → Telecommunications |
| FOGM | Fiber-Optic Guided Missile | In English | → Military engineering → Telecommunications |
| FOH | First-Order Hold | In English | |
| FOI | Field Operations Installation | In English | |
| FOIH | Flight Operations Integration Handbook | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOIRL | Fiber-Optic Inter-Repeater Link | In English | → Telecommunications |
| FOLD | Federally-Owned LANDSAT Data | In English | → Spaceflight engineering, astronautics |
| FOLED | Flexible Organic Light-Emitting Diode | In English | |
| FOM | Field Operations Memorandum | In English | |
| FOMR | Flight Operations Management Room | In English | |
| FOP | Flight Operations Plan | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOP | Facility Operations Plan | In English | |
| FOP | Follow-On Production | In English | |
| FOP | Flight Operations Panel | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOPG | Flight Operations Planning Group | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FoPh | Foundations of Physics | In English | → Serial publications, periodicals → Physics |
| FOPL | First Order Predicate Logic | In English | → Computer science → Mathematics |
| FOPP | Follow-On Parts Production | In English | |
| FOPS | Flight Operations Planning Schedule | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOPSS | Flight Operation Product Scheduling System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOR | Field Of Regard | In English | |
| FOR | Flight Operations Review | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FORC | Fiber Optics Research Center | In English | |
| FORD | Flight Operations Requirement Document | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FORTRAN | Formula Translation | In English | → Programming languages |
| FORU | Federation of Oceania Rugby Union | In English | → Organizations and associations → Football and rugby |
| FOS | Flight Operations Support | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOS | Flight Operation Security | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOS | Faint Object Spectrograph | In English | → Physics → Analytical chemistry |
| FOSA | Flight Operations Support Annex | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOSDIC | Film Optical Sensing Device for Input to Computers | In English | → Computer science |
| FOSMS | Facility Operation Scheduling and Monitoring System | In English | |
| FOSO | Flight Operations Scheduling Officer | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOSP | Flight Operations Support Personnel | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOST | Flight Operations Support Team | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOT | Flight Operations Team | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOT | Flight Operation Trainer | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FOV | First Orbital Vehicle | In English | → Spaceflight engineering, astronautics |
| FOWG | Flight Operations Working GRoup | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FP | Flexible Processor | In English | |
| FP | Flat Panel | In English | |
| FP | Fixed Point | In English | |
| FP | Fuel Pressure | In English | → Vehicle engineering |
| FP | Fixed Price | In English | → Economics |
| FP | Flight Plan | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FP | Focal Plane | In English | → Physics |
| FP | Freezing Point | In English | → Physics |
| FPA | Focal Plane Array | In English | → Physics |
| FPA | Focal Plane Assembly | In English | → Physics |
| FPB | Fuel Preburner | In English | → Vehicle engineering |
| FPB | Forum of Private Businesses | In English | → Organizations and associations |
| FPBOV | Fuel Preburner and Oxidizer Valve | In English | → Vehicle engineering |
| FPC | Forward Power Controller | In English | |
| FPC | Fixed-Price Contractor | In English | → 3474 |
| FPC | Federal Power Commission | In English | → Electrical engineering |
| FPCA | Forward Power Controller Assembly | In English | |
| FPD | Flight Projects Directorate | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FPDE | Focal Plane Drive Electronics | In English | → Electronics |
| FPE | Functional Program Element | In English | |
| FPEG | Fast-Pulse Electron Gun | In English | |
| FPGA | FIeld-Programmable Gate Array | In English | → Hardware → Electronics |
| FPGA | Field Programmable Gate Array | In English | → Electronics |
| FPH | Flight Procedures Handbook | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| FPhL | Foundations of Physics Letters | In English | → Serial publications, periodicals → Physics |
| FPI | Fixed-Price Incentive | In English | → Economics |
| FPI | Fuel Pressure Indicator | In English | → Vehicle engineering |
| FPIF | Fixed-Price Incentive Fee | In English | → Economics |
| FPIT | Field Preinstallation Test | In English | |
| FPL | Fetch Pointer List | In English |