ENGLISH
REFERENCE

watershed

n. · adj.
US //ˈwɑtɝˌʃɛd// UK //wˈɔːtəʃˌɛd// wa·ter·shed
  1. 1 television boundary (n.)
    C1 Advanced British English Theatre

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

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

    Example

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

    Example

    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. 2 drainage area (n.)
    C2 Proficiency American English Technical Science

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

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

    Example

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

    Example

    The local government implemented new zoning laws to protect the watershed from industrial runoff that threatened the city's primary reservoir.
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  1. 3 geographical ridge (n.)
    C2 Proficiency British English Technical Science

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

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

    Example

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

    Example

    The continental watershed determines the ultimate destination of snowmelt, directing it toward either the Atlantic or the Pacific Ocean.
  2. 4 marking a change (adj.)
    C1 Advanced Formal

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

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

    Example

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

    Example

    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
Origin

From water + shed. A calque of German Wasserscheide.

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