The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Eurasia and Africa to the east, and the Americas to the west. As one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The equator subdivides it into the North Atlantic Ocean and South Atlantic Ocean. With a total area of about 106,400,000 square kilometers, it covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. The volume of the Atlantic is 323,600,000 cubic kilometers. The average depth of the Atlantic is 3,926 meters. (2,147 fathoms; 12,881 ft). The greatest depth is 8,380 metres.The Atlantic's width varies from 2,848 km between Brazil and Sierra Leone 6,400 km in the south.
The oldest known mention of "Atlantic" is around 450 BC. Before Europeans discovered other oceans, their term "ocean" was synonymous with the waters beyond the Strait of Gibraltar that are now known as the Atlantic. The early Greeks believed this ocean to be a gigantic river encircling the world.