| UCT | Pythia.Services.Time, Pythia |
| uncurry | Pythia.Prelude |
| undefined | Pythia.Prelude |
| Universal | Pythia.Services.Time, Pythia |
| unless | Pythia.Prelude |
| unPercentage | Pythia.Data.Percentage.Internal, Pythia.Data.Percentage |
| unsafePercentage | Pythia.Data.Percentage |
| UPowerParseError | Pythia.Services.Battery.UPower |
| UPowerParseErrorPercentage | Pythia.Services.Battery.UPower |
| UPowerParseErrorStatus | Pythia.Services.Battery.UPower |
| UrlSource | Pythia.Services.GlobalIp.Types, Pythia.Services.GlobalIp, Pythia |
| US__Alaska | Pythia.Services.Time, Pythia |
| US__Aleutian | Pythia.Services.Time, Pythia |
| US__Arizona | Pythia.Services.Time, Pythia |
| US__Central | Pythia.Services.Time, Pythia |
| US__Eastern | Pythia.Services.Time, Pythia |
| US__East_Indiana | Pythia.Services.Time, Pythia |
| US__Hawaii | Pythia.Services.Time, Pythia |
| US__Indiana_Starke | Pythia.Services.Time, Pythia |
| US__Michigan | Pythia.Services.Time, Pythia |
| US__Mountain | Pythia.Services.Time, Pythia |
| US__Pacific | Pythia.Services.Time, Pythia |
| US__Samoa | Pythia.Services.Time, Pythia |
| UTC | Pythia.Services.Time, Pythia |
| utctDay | Pythia.Services.Time, Pythia |
| utctDayTime | Pythia.Services.Time, Pythia |
| UTCTime | |
| 1 (Type/Class) | Pythia.Services.Time, Pythia |
| 2 (Data Constructor) | Pythia.Services.Time, Pythia |