| Term | Definition | Pronunciation |
| W | watt | |
| W/U | workup | |
| w/v. | weight in volume | |
| wart | Benign epidermal growth. | |
| WBC | white blood cell; white blood count | |
| WD | well-developed | |
| weal | A bump raised on the skin caused by a lash or blow. | |
| weaning | The replacement of mother's milk in the diet of a young child with other food. | |
| wheal | A small swelling on the skin, as from an insect bite, that usually itches | hwēl |
| wheeze | Adventitious lung sounds that are continuous with a musical quality. They can be high or low pitched. | |
| whey | The liquid components of milk that remain after the casein, fat, and fat soluble components have been removed. | |
| white coat hypertension | Phenomenon where blood pressure readings are elevated only when taken in clinical settings. | |
| white matter | The region of central nervous system that appears lighter in color than the other type, gray matter. it mainly consists of myelinated nerve fibers and contains few neuronal cell bodies or dendrites. | |
| WHO | World Health Organization | |
| whooping cough | A respiratory infection caused by Bordetella pertussis and characterized by paroxysmal coughing ending in a prolonged crowing intake of breath. | |
| WN | well-nourished | |
| WNL | within normal limits | |
| WOP | without pain | |
| WPW | Wolff-Parkinson-White syndrome | |