Ocean smoothly into oceans of supercritical hydrogen. The atmosphere of Venus is 96.5% carbon dioxide, which is a supercritical fluid at its surface. On other bodies: 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
Indian Ocean Australasia Southern Indian Ocean Indian Ocean The Indian Ocean is the third largest of the world's oceanic divisions, covering (approximately 20% of the water on the Earth's surface). It is bounded by Asia on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean or, depending on definition, by Antarctica. It is named after India. Called the Sindhu Mahasagara or the great sea of the Sindhu by the Ancient Indians, this Ocean has been variously called Hindu Ocean, Indic Ocean, etc. in various languages. The Indian Ocean was also known