hydrosphere
Scientific term for the total water on Earth's surface, including oceans, lakes, rivers, and groundwater. Often used in earth science contexts.
See also: 水圏
boundary between water and land
Refers to the interface or border where water meets land, such as a shoreline or riverbank. Less common than the hydrosphere sense.
Diverse organisms inhabit the boundary between water and land.
The hydrosphere covers about 70% of the Earth's surface.
Compound of 水 (water) and 界 (world, boundary). The hydrosphere sense likely derives from the 'water world' interpretation, while the boundary sense uses 界 in its 'border' meaning.