noun

1. The topographical boundary dividing two adjacent catchment basins, such as a ridge or a crest.

2. A region of land within which water flows down into a specified body, such as a river, lake, sea, or ocean; a drainage basin.

3. A critical point marking a change in course or development.

Synonyms: divide, drainage divide, water divide, water parting, turning point, catchment, catchment area, catchment basin

adjective

1. Serving to mark a significant development, change in direction, etc.