English Reference
noun · adjective

watershed

n. · adj.
US /ˈwɑtɝˌʃɛd/ UK /wˈɔːtəʃˌɛd/ wa·ter·shed UK spelling watersheds

  1. 01 C1 Advanced British English Theatre

    n.the time of day (usually 9:00 PM) after which TV channels can show programs for adults.

    n.the time limit after which television broadcasters may air content unsuitable for children, such as violence or profanity.

    Simple

    The documentary was shown after the watershed because it contained strong language.

    In context

    Broadcasters must ensure that any material featuring graphic violence is scheduled well after the nine o'clock watershed to protect younger viewers.

    Usage

    usually used with the definite article 'the'

  2. 02 C2 Proficiency American EnglishTechnical Science

    n.an area of land where all the water flows into the same river or lake.

    n.the entire geographical area that drains into a particular river, lake, or reservoir.

    Simple

    Pollution in the upper watershed can affect the water quality of the entire river.

    In context

    The local government implemented new zoning laws to protect the watershed from industrial runoff that threatened the city's primary reservoir.

  3. 03 C2 Proficiency British EnglishTechnical Science

    n.a line of high land that separates two different river systems.

    n.the topographical ridge or line of high ground that separates two adjacent drainage basins.

    Simple

    The hikers stood on the watershed, where rain on one side flowed east and on the other side flowed west.

    In context

    The continental watershed determines the ultimate destination of snowmelt, directing it toward either the Atlantic or the Pacific Ocean.

  4. 04 C1 Advanced Formal

    adj.describing an event that is extremely important and changes everything that follows.

    adj.functioning as a modifier to describe an event or period that serves as a significant turning point.

    Simple

    The court's watershed decision changed the law for everyone in the country.

    In context

    The treaty was a watershed event in international diplomacy, ending decades of border disputes between the two neighbouring powers.

    Usage

    always used before a noun

His death became a watershed moment in rap history.

Al Jazeera· 17 Aug 2026

But the year 1923 has been recognized as a watershed for sardine fishing in the region.

The Conversation· 14 Aug 2026

From water + shed. A calque of German Wasserscheide.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Frequent
Updated