Engelsk definition
A partially enclosed body of water, and its surrounding coastal habitats, where saltwater from the ocean mixes with fresh water from rivers or streams. The resulting mixture of seawater and fresh water is called brackish water and its salinity can range from 0.5 to 35 ppt. (accessed http://oceanservice.noaa.gov/education/kits/estuaries/estuaries01_whatis.html)