i
Yes, it is correct.
The mouth of a stream is where the stream flows out into a larger body of water.
Lake
tributary
tributary
tributary
tributary
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.
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
This is the water cycle.
River, stream, waterway, brook, canal, or watercourse