There are only five named oceans: the Arctic, Atlantic, Indian, Pacific and Southern Oceans. By some accounts, the Seven Seas include both South and North Pacific and Atlantic bodies of water, accounting for the two additional seas.
The ancient phrase ?Seven Seas? is a figurative term referring to all the seas and oceans of the world, but which specific seven bodies of water are included depends on the historical time period.
Use of the term "Seven Seas" goes back thousands of years, but its exact origin remains uncertain. At various times in history, the Seven Seas referred to different bodies of water along trade routes, regional bodies of water, and even unknown bodies of water in faraway corners of the world.
The phrase entered Western literature from Greek texts in which the term included the Aegean, Adriatic, Mediterranean, Black and Red, and Caspian Seas and the Persian Gulf. Later, Medieval European literature referred to the Seven Seas as the North Sea, Baltic, Atlantic, Mediterranean, Black, Red and Arabian Seas. The concept changed once again after Europeans traveled to North America, when mariners referred to the Seven Seas as the Arctic, the Atlantic, the Indian, the Pacific, the Mediterranean, the Caribbean and the Gulf of Mexico.