The Mediterranean Sea (35 degrees north, 18 degrees east) is a sea of the Atlantic Ocean almost completely enclosed by land: on the north by Europe, on the south by Africa, and on the east by Asia. It covers an approximate area of 2.5 million km² (965,000 mi²), but its connection to the Atlantic (the Strait of Gibraltar) is only 14 km (9 mi) wide. In oceanography, it is sometimes called the Eurafrican mediterranean sea or the European Mediterranean Sea, to distinguish it from mediterranean seas elsewhere.

It was a superhighway of transport in ancient times, allowing for trade and cultural exchange between emergent peoples of the region — the Mesopotamian, Egyptian, Semitic, Persian, Phoenician, Carthaginian, Greek and Roman cultures. The history of the Mediterranean is crucial to understanding the origin and development of Western Civilization.

The term Mediterranean derives from the Latin mediterraneus, 'inland' (medius, 'middle' + terra, 'land, earth'). To the ancient Romans, the Mediterranean was the center of the Earth as they knew it.

The term mediterranean or Mediterranean Sea may also be used to describe any salty body of water that is largely surrounded by land, having a limited exchange of water with the Ocean. Thus, the Arctic Ocean is sometimes described as "a mediterranean sea" by persons who argue against its status as an ocean.