- united nations day
- Unguiculata
- unguiculate
- unguiculate mammal
- ungulate
- unbox
- urodynia
- ulalgia
- unspeakable
- unpalatability
- upsilon
- uptown
- united arab emirate dirham
- undecagon
- unqualified
- usefulness
- uncertainty
- ulteriority
- unboundedness
- understandability
- up quark
- United States dry unit
- unquenchable
- unemployment line
- undefined
- unevenly
- unmercifulness
- united states treasury
- uropygium
- urban typhus
- unit price
- unfermented
- unhappiness
- unidir
- unattractiveness
- unsightliness
- uygur
- urga
- umbel_like
- United Nations Office for Drug Control and Crime Prevention
- United Nations Educational Scientific and Cultural Organization
- United Nations International Children's Emergency Fund
- United Nations Crime Prevention and Criminal Justice
- United Nations Children's Fund
- ungetatable
- unexplainable
- unlicensed
- unlicenced
- unrealizable
- unlooked_for