watersh

n. [ Cf. G. wasserscheide; wasser water + scheide a place where two things separate, fr. scheiden to separate. ] [ 1913 Webster ]

1. The whole region or extent of country which contributes to the supply of a river or lake. [ 1913 Webster ]

2. 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; -- called also divide and water parting. [ 1913 Webster +PJC ]

3. a point in time marking an important transition between two situations, or phases of an activity; a turning point. [ PJC ]