A watershed is the area separating two different drainage basins/river systems.
It isn't divide that's for sure.
The Yalu River divides China and North Korea.
The young of a cow is a calf, regardless of the breed but if you wanted to be more specific you could call it a Highland calf or you could be more precise and say it is a Highland heifer calf or Highland bull calf.
It is called the highland dress.
It is the solidus line that separates the numerator from the denominator in a fraction
horizon
Brazilians call amazon river :river sea
highland
euphrat
Its either called a venscule or a vinculum.
thresh-hold
What did the Romans call the river thames
the source of the river