There is no single name for a single stream of water that flows into an ocean but headwaters would be a good one for a single stream of water into a lake
It's called a delta
current people
An ocean current.
The stream of water which flows like a river through the ocean is a current. The Gulf Stream is the most significant such current which flows from the tropics to the northern latitudes.
tributary
tributary
tributary
tributary
black
Ocean current
currents
current people
It is called a tributary. That is a very easy question that you should know!