Pronunciation: (wô'tur-shed", wot'ur-), [key]
1. Chiefly Brit.the ridge or crest line dividing two drainage areas; water parting; divide.
2. the region or area drained by a river, stream, etc.; drainage area.
3. Archit.wash (def. 48).
4. an important point of division or transition between two phases, conditions, etc.: The treaty to ban war in space may prove to be one of history's great watersheds.
constituting a watershed: a watershed area; a watershed case.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.