water
The river that flows from Lake Erie to the Atlantic Ocean is the Niagara River, which connects Lake Erie to Lake Ontario. From Lake Ontario, water flows into the Saint Lawrence River, which eventually leads to the Atlantic Ocean. This route is part of the Great Lakes-St. Lawrence Seaway system, facilitating the movement of water and shipping between the lakes and the ocean.
A delta.
Deltas
The Kennebec River.
tributary
tributary
tributary
tributary
The Kennebec River.
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
The Amazon river flows into the Atlantic Ocean.
stream, creek or either a lake or a ocean