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.
1 Being overweight: Excess body mass can decrease blood circulation, causing fluid to build up in the feet, legs, and ankles.  Standing or sitting for long periods: When the muscles are inactive, they canât pump body fluids back up toward the heart. The retention of water and blood can cause swelling in the legs.