| Abbreviation | Definition |
|---|---|
| ERFA | Essential Routines for Fundamental Astronomy |
| ESA | European Space Agency |
| ESAC | European Space Astronomy Center |
| ESAC | European Space Astronomy Centre |
| ESD | Earth System Dynamics |
| ESO | European Southern Observatory |
| ESTEC | European Space Research and TEChnology Center |
| ET | Ephemeris Time (now obsolete) |
| ETBD | Early Type Brown Dwarf |
| ETI | Extra-Terrestrial Intelligence |
| EU | Expanded Universe |
| EU | Extended Universe |
| EUSO | Extreme Universe Space Observatory |
| EVAC | East Valley Astronomy Club |
| EVGA | European VLBI Group for Geodesy and Astrometry |
| EXO | Extra Solar Planet |
| F | Fraunhofer lines |
| FAMOUS | Funds for Astronomical Meetings Outreach to Underrepresented Scientists |
| FAS | Federation of Astronomical Societies |
| FAT | Filtered Array Technology |