Water retention: A nonspecific term meaning the accumulation of excess fluids in body tissues, medically known as edema. Edema can result from many different disease processes, including but not limited to diseases of the heart and circulation and kidney disease.
Water retention is also used to describe the symptoms of feeling bloated or experiencing a small weight gain due to physiologic shifts in body fluid balance brought on by dietary changes, hormonal factors, or dehydration. In this sense water retention is described as a common symptom of the premenstrual syndrome, or PMS. See also edema.