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
Ocean current hemisphere due to imposed wind stresses. In these wind-driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. In addition, the areas of surface ocean currents move somewhat with the seasons; this is most notable in equatorial currents. Deep ocean basins generally have a non-symmetric surface current, in that the eastern equatorward-flowing branch is broad and diffuse whereas the western poleward flowing branch is very narrow. These western boundary currents (of which the Gulf Stream is an example) are a consequence of the rotation of the Earth. Deep ocean currents are driven