1. watershed - Noun
2. watershed - Adjective
The whole region or extent of country which contributes to the supply of a river or lake.
The line of division between two adjacent rivers or lakes with respect to the flow of water by natural channels into them; the natural boundary of a basin.
Source: Webster's dictionaryThe establishment of a free Iraq at the heart of the Middle East will be a watershed event in the global democratic revolution. George W. Bush
Equally, though, there are guys who play England Under 19 who don't even play First Class cricket. It is a watershed in the careers in many ways. Andy Pick
The great watershed of modern poetry is French, more than English. Robert Morgan
The advent of self-government for the Iraqi people is a watershed moment in their history. Todd Akin
Today I can announce a raft of reforms that we estimate could save over 2.5 million police hours every year. That's the equivalent of more than 1,200 police officer posts. These reforms are a watershed moment in policing. They show that we really mean business in busting bureaucracy. Theresa May
As costly as it was in the lives of our men and women in uniform, in military assets, and in esteem and pride, Pearl Harbor was a watershed moment for America. Joe Baca