watershed

noun
1
an event or a period of time that marks an important change
نقطه عطف, دوران سرنوشت‌ساز, رویداد مهم, لحظه تعیین‌کننده
2
a line of high land where streams on one side flow into one river, and streams on the other side flow into a different river
تقسیم‌آب, مرز حوضه‌های آبی, مرز حوضه آبریز, خط تقسیم جریان
3
(in the UK) the time before which programmes that are not considered suitable for children may not be shown on television
مرز پخش, ساعت ممنوعیت
the 9 o’clock watershed