- Ur
- uracil
- uraemia
- uraemic
- Ural Mountains
- Ural-Altaic
- Uralic
- Uralic language
- Urals
- uranalysis
- Urania
- uraninite
- uranium
- uranium 235
- uranium 238
- uranium ore
- uranologist
- uranology
- uranoplasty
- Uranoscopidae
- Uranus
- uranyl
- uranyl group
- uranyl nitrate
- uranyl oxalate
- uranyl radical
- urarthritis
- urate
- uratemia
- uraturia
- urban
- urban area
- urban center
- urban guerrilla
- Urban II
- urban legend
- urban planning
- urban renewal
- urban sprawl
- urban typhus
- Urban V
- Urban VI
- Urban VIII
- Urbana
- urbane
- urbanely
- urbanisation
- urbanise
- urbanised
- urbanity
- urbanization
- urbanize
- urbanized
- urceolate
- urceole
- urchin
- Urd
- Urdu
- urea
- urea-formaldehyde resin
- urease
- Uredinales
- uremia
- uremic
- ureter
- ureteritis
- ureterocele
- ureterorenal reflux
- ureterostenosis
- urethane
- urethra
- urethral
- urethral orifice
- urethral sphincter
- urethritis
- urethrocele
- Urex
- Urey
- Urga
- urge
- urge incontinence
- urge on
- urgency
- urgent
- urgently
- Urginea
- Urginea maritima
- urging
- Uria
- Uria aalge
- Uria lomvia
- Uriah
- urial
- uric
- uric acid
- uricaciduria
- uricosuric
- Urim and Thummim
- urinal
- urinalysis
- urinary
- urinary apparatus
- urinary bladder
- urinary calculus
- urinary hesitancy
- urinary incontinence
- urinary organ
- urinary retention
- urinary system
- urinary tract
- urinary tract infection
- urinate
- urination
- urinator
- urine
- uriniferous tubule
- URL
- Urmia
- urn
- urn fungus
- urn-shaped
- Urnula craterium
- urobilin
- urobilinogen
- urocele
- urochesia
- urochezia
- urochord
- Urochorda
- Urochordata
- urochordate
- Urocyon
- Urocyon cinereoargenteus
- Urocystis
- Urocystis cepulae
- Urocystis tritici
- urodele
- Urodella
- urodynia
- urogenital
- urogenital apparatus
- urogenital cleft
- urogenital medicine
- urogenital system
- urokinase
- urolith
- urologist
- urology
- uropathy
- Urophycis
- Uropsilus
- Uropsilus soricipes
- Uropygi
- uropygial gland
- uropygium
- Urosaurus
- Urosaurus ornatus
- Ursa Major
- Ursa Minor
- Ursidae
- ursine
- ursine dasyure
- ursinia
- Ursus
- Ursus americanus
- Ursus arctos
- Ursus arctos horribilis
- Ursus arctos middendorffi
- Ursus arctos syriacus
- Ursus horribilis
- Ursus Maritimus
- Ursus middendorffi
- Ursus thibetanus
- Ursus ursinus
- Urth
- Urtica
- Urtica dioica
- Urtica pipulifera
- Urticaceae
- Urticales
- urticaria
- urticate
- urtication
- Urubupunga
- Urubupunga Falls
- Uruguay
- Uruguay potato
- Uruguay potato vine
- Uruguay River
- Uruguayan
- Uruguayan monetary unit
- Uruguayan peso
- urus