- watershed, water parting, divide - a ridge of land that separates two adjacent river systems
--1 is a kind of line
--1 has particulars: continental divide; Great Divide - landmark, turning point, watershed - an event marking a unique or important historical change of course or one on which important developments depend; "the agreement was a watershed in the history of both nations"
--2 is a kind of juncture, occasion
--2 has particulars: Fall of Man; road to Damascus