| Acronym | Definition |
|---|
| EF | Electronic Warfare Fighter (US military aircraft designation) |
| EF | Electronic Filing |
| EF | Education First (internation English school) |
| EF | Environmentally Friendly (various organizations) |
| EF | Expedited Forwarding |
| EF | Ejection Fraction (cardiology) |
| EF | Entity Framework (software) |
| EF | Equivalent Focal Length |
| EF | Energy Factor |
| EF | Elongation Factor (protein synthesis) |
| EF | Executive Function |
| EF | Ejection Fraction |
| EF | Education Foundation (various organizations) |
| EF | Emergency Fund |
| EF | Eagle Forum |
| EF | Extra Fine (threads) |
| EF | Experimental Forest (USDA) |
| EF | Electric Field |
| EF | Emission (s) Factor |
| EF | Elite Force (Star Trek: Voyager computer game) |
| EF | Enhanced Fujita Scale (tornadoes) |
| EF | Extremely Fine (numismatics; 7th best condition of coin) |
| EF | End Function |
| EF | Equifax (credit reporting agency) |
| EF | Ecological Footprint |
| EF | Epic Fail (Internet slang) |
| EF | Entry Fee |
| EF | Electronic Form |
| EF | Exhaust Fan |
| EF | Echinaforce |
| EF | External Forces |
| EF | Elegant Feeling (Hyundai) |
| EF | Edema Factor (microbiology; bacillary subunit of anthrax) |
| EF | Equipment Failure (Wandel Goltermann) |
| EF | Enemy Forces |
| EF | Environmental Factor (The Olewine Company) |
| EF | Exposed Facility |
| EF | Ephedrine Free (thermogenic formula) |
| EF | Elmer Fudd (cartoon) |
| EF | Early Finish |
| EF | Electron Flow |
| EF | Europæiske Fællesskab (Danish: European Community) |
| EF | Emma Frost |
| EF | Enrichment Factor |
| EF | Elementary Functions (TMN) |
| EF | Operation Enduring Freedom (US DoD) |
| EF | Educational Forum |
| EF | Experience Factory |
| EF | End Fitting |
| EF | Engineering Fundamentals |
| EF | Emitter Follower |
| EF | Elementary File |
| EF | Excitation Frequency |
| EF | Elizabeth Forward (school district, Pennsylvania) |
| EF | Enterprise Framework |
| EF | Elite Four (gaming, Pokemon) |
| EF | Elbow Flexor |
| EF | Encircled Flux (fiber optics) |
| EF | Electro-Focus (Canon Cameras) |
| EF | English Finish |
| EF | Electronic Focusing |
| EF | Escuela de la Fe (Spanish) |
| EF | Eris Free (Internet Relay Chat network) |
| EF | Extension Flag |
| EF | Endgame Framework (modeling and simulation) |
| EF | Encyclopedia Frobozzica (Zork adventure game) |
| EF | Extended Fractal |
| EF | Electro-Flechette (gaming, Missionforce: Cyberstorm) |