Word Origin and History for tertiary Expand. adj. 1650s, of the third order, rank, degree, etc., from Latin tertiarius of or pertaining to a third, from tertius third, a third, from root of tres three (see three).
Water and Fluid retention in legs, also known as edema, is a medical condition caused by abnormal accumulation of water or fluids in the bodyâs tissues. Though excess water can be accumulated anywhere in the body, the most common areas are the ankles and legs.
Photo Credit mktordonez/iStock/Getty Images. 1  Edema, also known as fluid retention or water retention, is caused by the accumulation of excess fluids in the circulatory system and areas between the body's cells. It can cause different body parts to swell, with the face, hands, feet, ankles and legs being most common.