Ocean Ocean An ocean () 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. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. The word "ocean" is often used interchangeably with "sea" in American English. Strictly speaking, a "sea" is a body of saline water (generally a division of the world ocean) partly or fully enclosed by land, though "the sea" refers also to the oceans. Saline water covers approximately and is customarily divided into
Flat Earth grounds by around 330 BC. Knowledge of the spherical Earth gradually began to spread beyond the Hellenistic world from then on. In the modern era, pseudoscientific flat Earth theories have been espoused by modern flat Earth societies and, increasingly, by unaffiliated individuals using social media. In early Egyptian and Mesopotamian thought, the world was portrayed as a disk floating in the ocean. A similar model is found in the Homeric account from the 8th century BC in which "Okeanos, the personified body of water surrounding the circular surface of the Earth, is the begetter of all life and possibly of