- umbilical vesicle
- umbilical vein
- umbra
- umbrella pine
- umbrella tent
- umbria
- umbrina
- umpteen
- umteenth
- un americanise
- un americanize
- ulex europaeus
- ulmus americana
- ulmus glabra
- ulmus laevis
- ulmus pumila
- ulmus rubra
- ulmus sarniensis
- ulster
- ultimate
- ultimacy
- ultimate end
- ultimately
- ultimateness
- ultimatum
- ultimo
- un come at able
- un get at able
- un_indian (in a contemptuous sense)
- unabandonable
- unabashed
- unable to reply back
- unable to help
- unaccented beat (in music)
- unacceptableness
- unacceptably
- unaccessible
- unaccommodating
- unaccompanied
- unaccomplished
- unaccomplishment
- unaccountability
- unaccustomed
- unachievably
- unacknowledged
- unacquainted
- unanswered
- unapparent
- unapparently
- unappealable