WATERSHED

landmark, turning point, watershed

(noun) an event marking a unique or important historical change of course or one on which important developments depend; “the agreement was a watershed in the history of both nations”

watershed, water parting, divide

(noun) a ridge of land that separates two adjacent river systems

Source: WordNet® 3.1

Etymology

Noun

watershed (plural watersheds)

(hydrology, UK, Ireland, Australia, New Zealand) The topographical boundary dividing two adjacent catchment basins, such as a ridge or a crest.

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

A critical point marking a change in course or development.

(Canada, British) 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)

Synonyms

• (boundary between two adjacent catchment basins): water parting, drainage divide, water divide, divide

• (drainage basin): catchment basin, catchment, catchment area, drainage area, river basin, water basin

• (time after which adult material may be broadcast): safe harbor (US)

• (critical point marking a change in course or development): turning point

Anagrams

• draw sheet, drawsheet

Source: Wiktionary

Wa"ter*shed`, n. Etym: [Cf. G. wasserscheide; wasser water + scheide a place where two things separate, fr. scheiden to separate.]

1. The whole region or extent of country which contributes to the supply of a river or lake.

2. The line of division between two adjacent rivers or lakes with respect to the flow of water by natural channels into them; the natural boundary of a basin.

Source: Webster’s Unabridged Dictionary 1913 Edition