water-shed

Noun

watershed (plural watersheds)

1. (Australia, Ireland, New Zealand, UK) The topographical boundary dividing two adjacent catchment basins, such as a ridge or a crest.
   • After Lesjaverk (23 miles) the eastern end of Lesjaskogsvatn is reached. This lake has the distinction of being a watershed. From the east end flows the Lågen, the great river that runs down Gudbrandsdal to Lake Mjøsa, while from the west end the Rauma River emerges to flow down to the Romsdalfjord.1956 September, M. D. Greville, “Through the Romsdal by Rail”, in Railway Magazine, page 594

   Synonyms:

   water parting, drainage divide, water divide, divide

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

   Synonyms:

   catchment basin, catchment, catchment area, drainage area, river basin, water basin

3. (figuratively) A critical point marking a change in course or development.
   • watershed moment — watershed event — watershed ruling

   Synonyms:

   turning point, crossroads

4. (Canada, UK) The time of day after which material of a more adult nature (e.g., violence, swear words, or nudity) may be broadcast on television or radio, either one permitted by law or one contrived from convention (e.g. when children are not watching).

   Synonyms:

   safe harbor

See all 5 meanings of watershed