watershed
[ waw-ter-shed, wot-er- ]
an important event that signals the beginning of a new era or phase
USE 1
The discovery of penicillin was a watershed in the field of medicine, revolutionizing the treatment of bacterial infections.
USE 2
The signing of the peace treaty was a watershed in the history of both nations, marking the end of decades of conflict.
USE 3
Her election to the presidency was seen as a watershed moment for gender equality in politics.
