| Abbreviation | Definition |
|---|---|
| ECEF | Earth-Centered, Earth-Fixed |
| ECO | Earth Crossing Object |
| ECT | Equator Crossing Time |
| EFRF | Earth Fixed Reference Frame |
| EGRET | Energetic Gamma-Ray Experiment Telescope |
| EGT | Enhanced Gravity Tractor |
| EHBH | Event Horizon of a Black Hole |
| EL | Enlarging Lens |
| EMB | Earth Moon Barycenter |
| EME | Earth-to-Moon-to-Earth |
| EMT | Emergency Medical Technician |
| ENE | East North East |
| EO | Earth Observatory |
| EOL | Earth Observing Laboratory |
| EOSL | Earth Observation Systems Laboratory |
| EPD | Expected Planetary Differences |
| EPIC | Earth Polychromatic Imaging Camera |
| EPIC | Ecliptic Plane Input Catalog |
| EPOS | European Project On the Sun |
| ERF | Energy Rejection Filter |