U

• congenital limb absence;

• in electrocardiography, an undulating deflection that follows the T wave;

• internal energy;

• International Unit of enzyme activity;

• Mann-Whitney rank sum statistic;

• potential difference (in volts);

• ulcer;

• ulna;

• ultralente [insulin];

• umbilicus;

• uncertain;

• unerupted;

• unit [JCAHO unapproved abbreviation];

• universal application [residency];

• unknown;

• unsharpness;

• upper;

• uracil;

• uranium;

• urea;

• urethra;

• uridine;

• uridylic acid;

• urinary concentration;

• urine;

• urology;

• uterus;

• uvula;

• volume velocity