Here's why:

* Watershed: This term refers to the entire area of land that drains into a particular river, lake, or ocean. The watershed is separated from neighboring watersheds by divides.

* Divide: This term refers to the specific topographic feature (usually a ridge or mountain range) that separates one watershed from another. It's the line that marks the point where water flows in opposite directions.

Example: The Continental Divide in North America separates the watersheds that drain to the Pacific Ocean from those that drain to the Atlantic Ocean and the Gulf of Mexico.