What's the meaning of the “shed” in “watershed”?

Question

It seems like a kind of house, if it is. I cannot grasp the meaning of watershed.

Answer 1

Oxford dictionary online says

shed2 …(of a tree or other plant) allow (leaves or fruit) to fall to the ground…

A watershed sheds water to either side in much the same way an umbrella or raincoat sheds water.

The British National Corpus has

"I seem to have a veritable Serpentine in my locks," said the newcomer, still shedding water and laughing wildly.

Frankenstein unbound. Aldiss, Brian.

Answer 2

The New Oxford American Dictionary says:

Early 19th century: from water + shed in the sense “ridge of high ground”, suggested by German *Wasserscheide¨, literally ‘water-divide’

It says of shed, in the sense “allow to fall to the ground”:

Old English sc(e)ādan [separate out (one selected group), divide,] also [scatter,] of Germanic origin; related to Dutch and German scheiden.

Answer 3

It's worth noting that the word watershed can also mean a critical point that marks a division or change of course.

Watershed is also the name given to the period of time in which programmes unsuitable for children can be shown on public television.

Answer 4

A watershed can also be defined as a geographical area - as in "The Mississippi watershed..." determined by the boundary of the drainage area of a watercourse or river.