Ὠκεανός

In Greek mythology, Okeanos (Ὠκεανός) was a Titan — son of Ouranos (Sky) and Gaia (Earth). He was not a sea. He was the great river that encircled the entire flat disk of the earth, flowing endlessly in a loop. Homer describes him in the Iliad as the origin of all rivers, springs, and seas. Every body of water on earth was, in Greek cosmology, a tributary of Okeanos.

The Greeks used okeanos to distinguish the vast outer water from their familiar Mediterranean, which they called simply 'our sea' (he hemetera thalassa) or later Mare Nostrum in Latin. Herodotus, writing around 440 BCE, was skeptical that Okeanos existed as an actual encircling river, but the name stuck for the unknown waters beyond the Pillars of Hercules — the Strait of Gibraltar.

Latin borrowed Oceanus directly, and Old French passed it to Middle English as ocean by the 13th century. The mythological Titan faded, but his name expanded. Where the Greeks had one Okeanos wrapping the world, European cartographers eventually divided the water into separate oceans — Atlantic, Pacific, Indian — each getting its own identity. The singular god became a plural geography.

The word's origin remains disputed. Some scholars connect it to the Semitic root *ʾōg, meaning 'to encircle.' Others link it to the Sanskrit aśáyāna, 'the one who lies around.' Neither theory is settled. What is certain is that the name of a primordial deity, older than Zeus in the Greek genealogy, is now printed on weather reports and shipping labels.