thalweg
 n.— «Then, former president, Saddam Hussein, disputed the Algiers Accord, which ruled the maritime border between the two countries ran along the median line of the deep-water channel, also known as the thalweg.» —“AM: Diplomatic scandal as Iran intercepts British naval vessels” by Kirsten Aiken Austral. Broadcasting Corp. (Ultimo, New South Wales) June 22, 2004. (source: Double-Tongued Dictionary)