I was told it was an "exotic stream."
It is called an ocean current or a river current. :)
The area where a freshwater river or stream enters the ocean is called an estuary. It is a coastal area of brackish water formed when freshwater enters the ocean.
A natural stream of water larger than a creek and emptying into an ocean is called a river. The longest river in the world is the Nile River in Africa.
A river.
current people
stream, creek or either a lake or a ocean
A river of water in the ocean might be a way to describe an ocean current, such as the Gulf Stream.
A stream or river called that flows into a larger stream or river is called a tributary.
Tributary
The mouth is the part of a river of stream where it meats a sea or ocean.
Tributary is the answer you are looking for, I believe.
There are two answers to this question based upon the way it is written. A. A large natural stream of water emptying into a large "body" is called a river; and B. A large natural stream of water emptying into a larger body can be called a tributary. Normally this is a smaller river than the "large body". Thus the Missouri River is a tributary of the Mississippi River.