| Acronym | Definition |
|---|
| ET | Eastern Time |
| ET | Entertainment Tonight (TV show) |
| ET | Extraterrestrial |
| ET | Elapsed Time |
| ET | End Time |
| ET | Economic Times (newspaper in India) |
| ET | Early Times (Kentucky bourbon) |
| ET | External Tank (US NASA; Space Shuttle) |
| ET | Enemy Territory |
| ET | Environmental Technology |
| ET | Engineering Technology |
| ET | Educational Technology (various schools) |
| ET | Ethiopia |
| ET | Execution Time |
| ET | Early Type (weapon) |
| ET | Elevated Temperature |
| ET | Electronic Transmission |
| ET | Exercise Time |
| ET | Electronic Technology |
| ET | End Tidal |
| ET | Expert Team |
| ET | Embryo Transfer |
| ET | Evan Turner (basketball player) |
| ET | Employment Training |
| ET | Early Termination |
| ET | Executive Team (various organizations) |
| ET | Emerging Technology |
| ET | Essential Tremor |
| ET | Experimental Therapeutics (cancer research) |
| ET | Effective Temperature |
| ET | Evaluation Team |
| ET | Emissions Trading |
| ET | Exercise Tolerance (cardiology) |
| ET | Enabling Technologies |
| ET | Electrical Test |
| ET | Energy and Technology |
| ET | Electronics Technician |
| ET | Endotracheal |
| ET | Endothelin |
| ET | Evapotranspiration |
| ET | Electronic Time |
| ET | Endotracheal Tube |
| ET | Eddy (Current) Testing (NDE method) |
| ET | Engineering Technician (NICET) |
| ET | Exit Time |
| ET | Edge Thickness (optics) |
| ET | Employment Tribunal (UK) |
| ET | Event Timer |
| ET | Emergency Telecommunications |
| ET | Employment Taxes |
| ET | Esotropia (form of strabismus) |
| ET | Ersatzteil (German: spare part) |
| ET | Ex Tempore (Latin: At That Time) |
| ET | Expansion Tank (water tank) |
| ET | Equal Temperament (musical tuning system) |
| ET | Enterprise Technology |
| ET | Elliptical Trainer |
| ET | Essential Thrombocythemia (overproduction of platelets) |
| ET | EtherTalk |
| ET | Elephant Talk |
| ET | Ethyl Group (Ch3ch2) |
| ET | Engineering Test |
| ET | Early Transcendentals (calculus education) |
| ET | End Transmission |
| ET | Extra Traffic |
| ET | End Transaction |
| ET | End Turn (gaming) |
| ET | Electrotransfer |
| ET | Engineering Times |
| ET | Earth Tech (Long Beach, California) |
| ET | Equivalent Training |
| ET | Electro-Thermal |
| ET | Exhaustive Testing |
| ET | Enhanced Technology |
| ET | Earth Terminal |
| ET | Embedded Training |
| ET | External Test |
| ET | Ejection Time |
| ET | Event Tree |
| ET | Ephemeris Time |
| ET | Electronic Tool |
| ET | Enhanced Telephone |
| ET | Ex Testamento (Latin: From Hi/Her Will, epigraphy) |
| ET | Ejército de Tierra (Spanish Army) |
| ET | Endurance Testing |
| ET | Enhanced Throughput |
| ET | Exponential Tail |
| ET | Enterostomal Therapist |
| ET | Earlsfort Terrace (University College, Dublin Campus) |
| ET | Enterprise Toronto |
| ET | Electronic Tongue |
| ET | Exchange Terminal |
| ET | FCC Office of Engineering and Technology |
| ET | Enterprise Transition (Strategy) |
| ET | Exchange Termination |
| ET | Exploring Transfer (Vassar College; Poughkeepsie, NY) |
| ET | Electrical Transcription |
| ET | Ethiopian Airlines Enterprise (IATA airline code) |
| ET | Energy Technology Programs |
| ET | Emergency Transaction |
| ET | Extrathoracic Region |
| ET | Escape Tone (music) |
| ET | Equitemperature |
| ET | Enhancement Traffic |
| ET | Ecotox Threshold (EPA) |
| ET | Electronic Technican |
| ET | Elogic Technologies Pvt Ltd. (India) |
| ET | Element Tracker (Sprint) |
| ET | Epstein Technique (oral history) |
| ET | Enhanced Trackwolf |
| ET | Eagle Talisman (amulet in game Shilla) |
| ET | Einrücktermin (German) |
| ET | (USN Rating) Electronics Technician |
| ET | Entomofauna of Turkey |