watershed

Meanings

• a ridge of land that separates two adjacent river systems
• the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet
• 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"

Synonyms

basin, catchment area, catchment basin, divide, drainage area, drainage basin, landmark, river basin, turning point, water parting