Umbilicus. The naval.

Unctuous. Fat; oily.

Urea. A nitrogenous constituent of the urine.

Urethra. The canal that conveys the urine from the bladder out of the body.

Urinometer. An instrument for obtaining the specific gravity of urine.

Utero Gestation. Pregnancy.

Uterus. The womb.

Varicose Veins. Veins that are morbidly enlarged.

Vascular. Full of blood vessels.

Vein. A vessel carrying blood to the heart.