/waw"teuhr shed', wot"euhr-/ , n.
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.
adj.
5. constituting a watershed: a watershed area; a watershed case.
[ 1795-1805; WATER + SHED 2 ]