watchful waiting (Also called expectant management.) - close monitoring of prostate cancer by a physician instead of immediate treatment.

watermelon stomach - parallel red sores in the stomach that look like the stripes on a watermelon.

wedge resection of the lung - a small, localized section of the lung is removed, often for a lung biopsy.

wen - sebaceous cyst that develops in the skin, especially the scalp.

wheezing - a whistling noise in the chest which occurs during breathing when the airways are compressed.

white blood cell - a type of cell in the immune system that helps the body fight infection and disease. White blood cells include lymphocytes, granulocytes, macrophages, and others.

whole blood - blood containing all its components, such as red and white blood cells, platelets, and more.

womb - the common term for uterus, a muscular organ inside which the baby grows during pregnancy.