If something such as an event is a watershed in the history or development of something, it is very important because it represents the beginning of a new stage in it.
例句
The election of Mary Robinson in 1990 was a watershed in Irish politics...1990年玛丽·鲁宾逊的当选是爱尔兰政治上的一个转折点。Tonight could prove to be a watershed for the international career of Barnes.今晚将可能成为巴恩斯国际职业生涯的转折点。
N-COUNT
(成人电视节目播出前的)分水岭时间
The watershed is a time before which television broadcasters have agreed not to show programmes unsuitable for children, for example programmes that contain scenes of sex or violence.
例句
Bad language before the watershed is widely resented...在成人节目时间之前出现的脏话深为众人憎恶。The advert should only be shown after the 9pm watershed.这则广告只能在晚上9点成人节目开始后才能播出。
N-COUNT
分水线；分水岭
A watershed is an area of high ground which divides two or more river systems, so that all streams on one side flow into one river and those on the other side flow into a different river.