An ocean (from Ancient Greek Ὠκεανός, transc. Okeanós, the sea of classical antiquity) is a body of saline water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean, which occupies two-thirds of the planet's surface. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern, and Arctic Oceans.
