World Ocean
The term World Ocean refers to the interconnected system of the planet Earth's marine waters. The term was coined by the Russian oceanographer Yuly Shokalsky in the early 20th century. The words Ocean and also Sea can be used synonymously. The world ocean is subdivided into the Atlantic Ocean, the Indian Ocean, the Pacific Ocean, the Arctic Ocean, and the Southern Ocean.
The Arctic Ocean, the smallest of the five, is spread around the North Pole, touching North America in the Western hemisphere and Scandinavia and Asia in the Eastern hemisphere. the Southern Ocean, the second smallest, encircles the Antarctic and its peripheral islands. Both, particularly the former, are partially covered in sea ice, the extent of which varies according to the season. The Atlantic Ocean, the second largest, extends from the Arctic Ocean to the Southern Ocean between North America, Europe and Africa. The Pacific, the largest of all, also reaches from one polar ocean to the other, spanning the gap between Asia, North America, Australia and Oceania. These two oceans have a short common border south of Cape Horn. The Indian Ocean connects the southeast end of the Atlantic to the southwest end of the Pacific, a connection to the Arctic Ocean is prevented by the presence of Asia.
The World Ocean's approximate shape can, for most purposes, be assumed constant, although in fact it is not. Continental drift has influenced its structure ever since its existence.