A ridge of land that separates two adjacent river systems.

synonyms: divide, water parting.

Dutch: waterscheiding, keerpunt
Polish: wododział, dział wodny, dział wód

The entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet.

synonyms: basin, catchment area, catchment basin, drainage area, drainage basin, river basin.

Dutch: bassin, bekken, afwateringsgebied, neerslaggebied, stroomgebied
Polish: dorzecze

An event marking a unique or important historical change of course or one on which important developments depend:
— The agreement was a watershed in the history of both nations.

synonyms: landmark, turning point.

Dutch: keerpunt, mijlpaal, monument
Polish: punkt