- 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.
Meaning of 'watershed' (Princeton's WordNet)
1 . watershed
[ n]
Meaning (1): - the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet
Example in sentence:
flood control in the Missouri basin
Meaning (2): - an event marking a unique or important historical change of course or one on which important developments depend
Example in sentence:
the agreement was a watershed in the history of both nations