| Abbreviation | Definition |
|---|---|
| UEY | Understanding the Early Years |
| UFR | UltraFlight Radio |
| UFR | Underground Film Revolution |
| UFW | Ultra Fast Woofer |
| UGA | Under- Ground Aces |
| UGC | User Generated Content |
| UGJ | Underground Japan |
| UGN | UnderGround News |
| UGU | Unix Guru Universe |
| UHM | Upcoming Horror Movies |
| UHR | UFO Historical Revue |
| UIU | Understanding the Integral Universe |
| UJB | Ultimate JukeBox |
| UJR | Under Jolly Roger |
| UK | Usher's Keep |
| UKA | United Kingdom Authors |
| UKA | UnKnown Abbreviation |
| UKP | United Kingdom Press |
| UKU | Udvalg for Kliniske Undersoegelser |
| UL | Using Linux |