Atlantic Ocean as the mid-19th century. During the Age of Discovery, the Atlantic was also known to English cartographers as the Great Western Ocean. The International Hydrographic Organization (IHO) defined the limits of the oceans and seas in 1953, but some of these definitions have been revised since then and some are not used by various authorities, institutions, and countries, see for example the CIA World Factbook. Correspondingly, the extent and number of oceans and seas varies. The Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea,
Indian Ocean Ocean. The term was still in use during the mid-18th century. The borders of the Indian Ocean, as delineated by the International Hydrographic Organization in 1953 included the Southern Ocean but not the marginal seas along the northern rim, but in 2000 the IHO delimited the Southern Ocean separately, which removed waters south of 60°S from the Indian Ocean, but included the northern marginal seas. Meridionally, the Indian Ocean is delimited from the Atlantic Ocean by the 20° east meridian, running south from Cape Agulhas, and from the Pacific Ocean by the meridian of 146°55'E, running south from the southernmost