watershed
//ˈwɔːtəʃɛd//
Noun
watershedSingular
watershedsPlural
1
A crucial turning point or dividing line marking a significant change in events, circumstances, or attitudes.
The discovery of penicillin was a watershed in the history of medicine.
2
An area of land that drains all the streams and rainfall to a common outlet such as a river, bay, or other body of water.
The watershed of this river covers several states.
3
A ridge of high land dividing two areas that are drained by different river systems.
The hikers reached the watershed that separates the two river valleys.