An ocean (from Greek ???????, Okeanos (Oceanus)) is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface, an area of some 361 million square kilometers (139.5 million square miles), is covered by ocean; a continuous body of water that is customarily divided into several principal oceans and smaller seas.
Southern Ocean, sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans
Arctic Ocean, sometimes considered a sea of the Atlantic