1. (noun) a ridge of land that separates two adjacent river systems

• divide
• water parting

2. (noun) the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet

• basin
• catchment area
• catchment basin
• drainage area
• drainage basin
• river basin

3. (noun) an event marking a unique or important historical change of course or one on which important developments depend

• landmark
• turning point

1. (noun) a ridge of land that separates two adjacent river systems

• continental divide

2. (noun) the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet

• detention basin
• retention basin

3. (noun) an event marking a unique or important historical change of course or one on which important developments depend

• fall of man
• road to damascus

1. (noun) a ridge of land that separates two adjacent river systems

• line

2. (noun) the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet

• geographic area
• geographic region
• geographical area
• geographical region

3. (noun) an event marking a unique or important historical change of course or one on which important developments depend

• juncture
• occasion

1. (noun) a ridge of land that separates two adjacent river systems

• divide
• separate