| Word | Definition | 
| UA | urinalysis | 
| UE | upper extremity | 
| ul/o | scar, gums | 
| ulcer | A lesion on the surface of a organ or tissue, produced by the sloughing of inflammatory necrotic tissue. | 
| -ule | small, small one | 
| ulna | The inner and longer bone of the forearm. | 
| ulnar | Pertaining to the ulna, the long medial bone of the forearm. | 
| ultra- | beyond | 
| ultrasonography | The visualization of deep structures of the body by recording the reflections of ultrasonic pulses directed into the tissues. | 
| ultraviolet | Electromagnetic radiation that has shorter wavelengths than visible light. | 
| -um | structure, tissue | 
| umbilic- | umbilicus (navel) | 
| umbilical | Pertaining to the opening in the abdominal wall where the blood vessels from the placenta enter. | 
| umbilical cord | The flexible rope-like structure that connects a developing fetus to the placenta. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus. | 
| umbilicus | The depression in the center of the abdominal wall where the umbilical cord entered in the fetus. Also called the navel. | 
| un- | not, reversal of an action | 
| unconsciousness | Abnormal loss of awareness of self and environment and lack of responsiveness to sensory stimuli. | 
| uncus | A hook-shaped structure. | 
| ung. | ointment | 
| ungu/o | nail | 
| ungual | Pertaining to the nails. | 
| unguis | A nail. | 
| uni- | one | 
| ur/o | urine | 
| uran/o | hard palate | 
| urea | A compound formed in the liver which is the major nitrogenous end product of protein metabolism | 
| uremia | Presence of excessive amounts of urea in the blood.  May be a sign of renal disease or failure. | 
| -uresis | urination | 
| ureter | One of a pair of tubes that transports urine from the kidney pelvis to the urinary bladder. | 
| ureter/o | ureter | 
| ureteral | Pertaining to the ureter. | 
| ureterocele | A cystic dilatation of the end of a ureter as it enters into the urinary bladder. It may obstruct urine flow. | 
| ureterolithiasis | Formation of stones in the ureter. | 
| ureterostomy | Surgical creation of an external opening in the ureter for external drainage of the urine. | 
| urethr/o | urethra | 
| urethra | A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. | 
| urethral | Pertaining to the urethra. | 
| urethritis | Inflammation of the urethra, causing painful and difficult urination. | 
| URI | upper respiratory infection | 
| -uria | urination | 
| urin/o | urine, urinary system | 
| urinalysis | Laboratory analysis of urine by chemical, physical, or microscopic means. | 
| urinary bladder | A muscular, membranous sac along the urinary tract that store urine until urination. | 
| urinary catheters | Catheters inserted into the urinary bladder or kidney for therapeutic or diagnostic purposes. | 
| urinary fistula | An abnormal passage in any part of the urinary tract between itself or with other organs. | 
| urination | Discharge of urine from the body. | 
| urine | The fluid containing waste products and water secreted by the kidneys, then stored in the urinary bladder until urination. | 
| urochesia | Passage of urine through the rectum. | 
| urolith | A stone in the urinary tract. | 
| urolithiasis | Formation of stones in any part of the urinary tract, usually in the kidney, urinary bladder or the ureter. | 
| urologic | Pertaining to urology. | 
| urology | A surgical specialty concerned with the study, diagnosis, and treatment of diseases of the urinary tract in both sexes, and the genital tract in the male. | 
| urothelium | The epithelial lining of the urinary tract. | 
| URT | upper respiratory tract | 
| urticaria | Hives, which are welts on the skin that often itch | 
| US | ultrasound | 
| USP | United States Pharmacopeia | 
| ut. dict. | as directed | 
| uter/o | uterus | 
| uterine | Pertaining to the uterus. | 
| uterine prolapse | A condition where the uterus drops down into the vagina. | 
| uterus | The womb. A female reproductive organ located between the bladder and the rectum. | 
| UTI | urinary tract infection | 
| UV | ultraviolet | 
| UVA | ultraviolet A light | 
| uve/o | uvea | 
| uveal | Pertaining to the uvea. | 
| uveitis | Inflammation of the uvea. | 
| uvula | A fleshy extension at the back of the soft palate that hangs above the opening of the throat. |