World Ocean

The world ocean, or global ocean is used to describe all the world's oceans as one large interconnected ocean. It is not a generally agreed term.
It is divided into the standard oceans: the Atlantic Ocean, Arctic Ocean, Indian Ocean, Pacific Ocean, and the proposed southern ocean around the Antarctic. 
The world ocean is mainly the southern oceans. The Atlantic, Indian, and Pacific Oceans can be seen as bays or lobes going northward from the Southern Ocean. Farther north, the Atlantic opens into the Arctic Ocean, which is connected to the Pacific by the Bering Strait:
The oceans of the world are not constant. Climate change happens, and so does continental drift over a much longer timescale.