Water divide is a geological term that refers to a line or ridge separating two adjacent watersheds, where water flows in opposite directions. Synonyms for water divide include watershed divide, drainage divide, water parting, and drainage basin boundary. A watershed divide is a high point in a watershed that determines the direction of water flow. A drainage divide is a ridge that separates one watershed from another. Water parting refers to the point at which water begins to flow downhill in opposite directions. Finally, the term drainage basin boundary refers to the area where two drainage basins meet and water begins to follow different paths. These synonyms are often used interchangeably to describe the same phenomenon.