| U | Integrated circuit (circuit diagram marking) 
| Others |
| U | Subsampled raw YUV file Bitmap graphics
| Others |
| U | The Uncompensated
| Others |
| U | The Usual
| Others |
| U | U-Bahn
| Others |
| U | Ugly
| Others |
| U | Uhf
| Others |
| U | Ultimate
| Others |
| U | Ultralente insulin
| Others |
| U | Umleitung
| Others |
| U | Unavailable
| Others |
| U | Uncertain
| Others |
| U | Unclassified
| Others |
| U | Uncommitted
| Others |
| U | Uncommon
| Others |
| U | Uncompromising
| Others |
| U | Unconditional
| Others |
| U | Und
| Others |
| U | Undecided
| Others |
| U | Undefeated
| Others |
| U | Undefined
| Others |
| U | Under
| Others |
| U | Underfloor
| Others |
| U | Undergirding
| Others |
| U | Understanding
| Others |
| U | Underwear
| Others |
| U | Undetectable
| Others |
| U | Undetected
| Others |
| U | Unexcelled
| Others |
| U | Unhappy
| Others |
| U | Unicode
| Others |
| U | Unidentified
| Others |
| U | Unification
| Others |
| u | Unified atomic mass unit
| Others |
| U | Uniform
| Others |
| U | Uninduced
| Others |
| U | Uninstall
| Others |
| U | Uninterpretable
| Others |
| U | Union
| Others |
| U | Unit
| Others |
| U | Unit(s)
| Others |
| U | United
| Others |
| U | Units
| Others |
| U | Unity
| Others |
| U | Universal
| Others |
| U | Universal Pictures
| Others |
| U | University
| Others |
| U | University of Utah
| Others |
| U | Unknown
| Others |
| U | Unlicensed
| Others |
| U | Unlimited
| Others |
| U | Unlocked
| Others |
| U | Unlucky
| Others |
| U | Unmodified
| Others |
| U | Unofficial
| Others |
| U | Unplasticised
| Others |
| U | Unredacted
| Others |
| U | Unreliable
| Others |
| U | Unsatisfactory
| Others |
| U | Unsigned
| Others |
| U | Unterseeboot
| Others |
| U | Unusual
| Others |
| U | Unwind tape
| Others |
| U | Up
| Others |
| U | Upbuilding
| Others |
| U | Update
| Others |
| U | Uphill
| Others |
| U | Upper
| Others |
| U | Upsilon
| Others |
| U | Uracil
| Others |
| U | Uranium
| Element |
| U | Urban
| Others |
| U | Urgent
| Others |
| U | Ursula
| Others |
| U | Use
| Others |
| U | Useless
| Others |
| U | User
| Others |
| U | Userid
| Others |
| U | Users
| Others |
| U | Wind Speed
| Others |
| U | You
| Others |
| u. | and (und, [German])
| Others |
| u. | and [und (German)]
| Others |
| u. | under (unter, [German])
| Others |