'Ocean' is named after the Titan Okeanos — a mythical river circling the Earth, reimagined for open water.
The vast body of salt water that covers approximately 71 percent of the Earth's surface. Also used to refer to any of the principal divisions of this body of water, such as the Atlantic, Pacific, Indian, Arctic, or Southern Ocean.
From Greek Ōkeanos (Ὠκεανός), originally the name of the great river or stream that the ancient Greeks believed encircled the flat disc of the Earth. In Greek mythology, Okeanos was a Titan, the personification of this world-encircling river and the father of all rivers, springs, and fountains. The word entered Latin as Oceanus and passed through Old
The ancient Greeks did not think of Okeanos as an ocean in our sense at all — he was a freshwater river that flowed in a perfect circle around the edge of the world. It was only after Greek navigators sailed beyond the Mediterranean into the Atlantic that the name shifted from a mythological river to mean a vast body of salt water.