In the UK, the boundary between two river systems. Horton (1945) GSA Bull. 56, 3 uses the term watershed line, and refers to drainage basins as separate entities, but watershed is now commonly used in North America to mean drainage basin; ‘the Mississippi River has the largest of all North American watersheds’ (Galler and Anderson (2008) GSA Bull. 120, 3).
Subjects: Meteorology and Climatology.