名詞 watershed:

1. a ridge of land that separates two adjacent river systems
   同義詞：water parting, divide
2. an event marking a unique or important historical change of course or one on which important developments depend
   同義詞：landmark, turning point

1. Leaving her first job was a watershed in her life.
   辭去她的第一份工作是她生活中的一個轉折點。
2. Her visit to India proves to be a watershed in her life.
   她的印度之行成了她一生的轉折點。
3. Her visit to India proved to be a watershed in her life.
   她的印度之行成了她一生的轉折點。

wa.ter.shed

n.（名詞）
A ridge of high land dividing two areas that are drained by different river systems.Also called water parting
分水嶺：將兩個不同水系流經地區(qū)分開的脊狀高地也作 water parting
The region draining into a river, river system, or other body of water.
流域：將水排入某河流、水系或其它水體的地域
A critical point that marks a division or a change of course; a turning point:
分水嶺，轉折點：標志著分界或過程改變的重要關頭；轉折點：
例句：
.a watershed in modern American history, a time that . . . forever changed American social attitudes.(Robert Reinhold)
.現(xiàn)代美國歷史的轉折點，一個…永遠改變了美國社會觀念的時刻.(羅伯特·賴恩豪德)

來源：
Probably translation of German Wasserscheide
可能為 德語 Wasserscheide的翻譯
Wasser [water]
Wasser [水]
Scheide [divide, parting]
Scheide [分開，分離]