watershed Noun The topographical boundary dividing two adjacent catchment basins, such as a ridge or a crest.
watershed Noun A region of land within which water flows down into a specified body, such as a river, lake, sea, or ocean; a drainage basin.
watershed Noun A critical point marking a change in course or development.
watershed Noun The time after which material of more adult nature (violence, swear words, sex) may be broadcast on television or radio, either one laid down or one contrived (e.g. when children are not watching...)