| FL | Florida (US postal abbreviation) | |
| FL | Fort Lauderdale (Florida) | |
| FL | Fort Lewis (Washington) | |
|
| FL | Flat | |
| FL | Filter | |
| FL | Flare | |
| FL | First Lady | |
| FL | French Lick (Indiana) | |
| FL | Flash (nautical navigation) | |
| FL | Finish Line | |
| FL | Foreign Language | |
| FL | Flight Line | |
| FL | Fluid | |
|
| FL | Fast Lane | |
| FL | Freightliner (truck manufacturer) | |
| FL | Front Line | |
| FL | Forward Looking | |
| FL | Flute | |
| FL | Fruityloops (audio software) | |
| FL | Flight Level | |
| FL | Flawless (diamonds) | |
| FL | Focal Length | |
| FL | Foot Locker | |
| FL | Flensburg (German city) | |
| FL | Fire Lake (Bob Seger Song) | |
| FL | Frito-Lay | |
| FL | Full Load | |
| FL | Fetlife (social application) | |
| FL | Florin (coin) | |
| FL | Facilities List | |
| FL | Fork Length (fish measurement) | |
| FL | Freelancer (computer game) | |
| FL | Fuzzy Logic | |
| FL | Flashing Light | |
| FL | Airtran (ICAO code) | |
| FL | Found Living (geneology) | |
| FL | Fluorine | |
| FL | Fuerstentum Liechtenstein | |
| FL | File List | |
| FL | Field Level (STARS Standard Accounting and Reporting System) | |
| FL | Fanlisting | |
| FL | Flanker (football position) | |
| FL | Force Level | |
| FL | Flerovium (chemical element) | |
| FL | Fluid Level | |
| FL | Flammable Liquid | |
| FL | Fluorescence Microscopy | |
| FL | Franz Liszt (classical composer) | |
| FL | Foot Loose | |
| FL | Floruit (Latin: Flourished) | |
| FL | Flowline | |
| FL | Financial Leverage | |
| FL | Femur Length | |
| FL | Forced Landing | |
| FL | Fault Location | |
| FL | Freie Liste (German: Free List, Liechtenstein) | |
| FL | Fiber-Optic Link | |
| FL | Face Left | |
| Fl | Flintholm (Danish railway station) | |
| FL | Fire Lord (video game) | |
| FL | Format Line | |
| FL | Fail Last | |
| FL | Foot-Lambert (luminance unit) | |
| fL | Femtoliter (10E-15 liter) | |
| FL | Frylock (cartoon character) | |
| FL | Floor Levelness (concrete construction) | |
| FL | Farben Lehre (Polish punk-rock band) | |
| FL | French Lop (breed of rabbit) | |
| FL | Flexible Link | |
| FL | Flagship Lounge (American Airlines first class lounge) | |
| FL | Functional Location | |
| FL | Failed Link | |
| FL | Ferretería Lewonski (Guatemalan buyer company) | |
| FL | Folded Letter | |
| FL | Fuller Lodge (Los Alamos, NM) | |
| FL | Foreign Lady | |
| FL | Functional Library | |
| FL | Flanker Back (football; old position) | |
| FL | Free Leech | |
| FL | Friedmann-Lemaître Metric (an exact solution of Einstein's field theory of relativity) | |
| FL | Faceoffs Lost (hockey) | |
| FL | Fachlehrkraft (German schools) | |
| FL | Floor Lieutenant | |
| FL | Flexileave (UK) | |
| FL | Federal Libertarian | |
| Fl | Lighting correction factor | |