watershed

Pluralwatersheds

1. 1
   river basinnounCanadaUScountable

   An area of land in which water drains down into a particular river, lake, sea, or ocean.

   Fertilizer washing off farms across the watershed is feeding algae blooms in the lake.

   The Mississippi River watershed stretches from the Rocky Mountains to the Appalachians.

   UsageIn some countries this area is a catchment, and watershed means the dividing ridge.

   Similarcatchment

   Note

   North American usage gives the word to the whole basin, the land that drains into one river or lake; in British, Irish, Australian and New Zealand usage it is the ridge that divides two basins, and the area is a catchment. So the same sentence can mean an area or a line depending on who wrote it, and a reader of international reports should check which. Source

   Checked 31 Oct 2026 · 1 fact

   • A drainage basin comprises land whose water drains into a common body of water. fisheries.noaa.gov
2. 2
   a turning pointnounfigurativelycountable

   A turning point that marks a decisive change in the course or development of something.

   The pandemic proved a watershed for remote work, and many offices never fully reopened.

   Historians see the election as a watershed in the country's politics.

   UsageUsually a watershed in or for something: a watershed in politics, for workers' rights.

   Similarcrossroads

   Note

   Rain falling on either side of the ridge between basins ends up in different rivers, and that is the picture behind the figure: a watershed is the point after which things run a different course. Writers apply it to industries and eras alike, as when the pandemic became a watershed for the railways, speeding the decline of season tickets and cutting business travel after years of growth. Source

   Checked 31 Oct 2026 · 5 facts

   • Rain on opposite sides of a drainage divide flows into different drainage basins. usgs.gov
   • The figurative meaning derives from the physical sense of a dividing line. worldwidewords.org
   • The pandemic accelerated changes in working practices associated with the existing decline in traditional rail season-ticket use. gov.uk
   • Business travel by rail declined following the pandemic. orr.gov.uk
   • The business rail market had been growing before the pandemic, as evidenced by the Business Travel Association's domestic rail revenue. committees.parliament.uk
3. 3
   adjective

   Marking a significant development or a change of direction.

   The court's ruling was a watershed moment for civil rights.

   Critics now call her second album a watershed release for the genre.

   UsageComes before a noun, most often a watershed moment or year; keep it for big, lasting changes.

   Similarpivotal, momentous, decisive, historic

   Oppositeinsignificant

4. 4
   dividing ridgenounAustraliaIrelandNew ZealandUKcountable

   The boundary in the landscape, such as a ridge or crest, that separates two neighboring drainage basins.

   The Pennines form the main watershed of northern England.

   The track follows the watershed for six kilometres, with streams falling away on either side.

   UsageAlso called a divide, especially in North America, where watershed usually means the whole basin.

   Similardivide

   Note

   German Wasserscheide, the place where the waters part, gave English its pattern, and water parting and divide say the same thing in plainer words. The line usually runs along high ground, but not always: the lake Lesjaskogsvatn sits on one, with the Lågen flowing from its eastern end down Gudbrandsdal and another river leaving from the west. Source

   Checked 31 Oct 2026 · 7 facts

   • English watershed was formed on the pattern of German Wasserscheide. en.wiktionary.org
   • Wasserscheide means a division or boundary between waters. en.wiktionary.org
   • Water parting and divide are synonyms of watershed in this geographical sense. en.wiktionary.org
   • A watershed generally follows high ground, but can cross lower terrain. en.wikipedia.org
   • Lesjaskogsvatn lies on a watershed. en.wikipedia.org
   • The lake drains east into the Lågen and west into another river, the Rauma. publikasjoner.nve.no
   • The Lågen flows through Gudbrandsdal. en.wikipedia.org
5. 5
   TV time limitnounBritishCanadauncountable

   The time of day from which television or radio may broadcast adult content, such as violence, swearing, or sex, under law or custom.

   The drama was moved to a slot after the watershed because of its violent scenes.

   Presenters on early-evening radio must keep their language clean until the watershed.

   UsageUsually the watershed, with before or after: shown after the watershed.

   Note

   Broadcasting in Britain and Canada names the line in the schedule after which adult material may air, whether set by law or by custom; American broadcasting calls the same window the safe harbor. The picture is still a dividing line, with family viewing on one side and adult programs on the other, so shows air before or after the watershed. Source

   Checked 31 Oct 2026 · 3 facts

   • British broadcasting has a regulated watershed after which material unsuitable for children may generally be shown. ofcom.org.uk
   • Canadian broadcasting uses a watershed to mark the start of the period for adult television content. cbsc.ca
   • American broadcasting calls the corresponding permitted period the safe harbor. docs.fcc.gov

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