Oceanus
Ὠκεανός
Oceanus is called βαθύρροος ("deep-flowing") and ἀψόρροος ("flowing back to itself, circular")
According to Homer, Oceanus was the ocean-stream at the margin of the habitable world (οἰκουμένη, oikouménē), the father of everything.
εἶμι γὰρ ὀψομένη πολυφόρβου πείρατα γαίης,
Ὠκεανόν τε θεῶν γένεσιν καὶ μητέρα Τηθύν,
οἵ μ' ἐν σφοῖσι δόμοισιν ἐὺ τρέφον ἠδ' ἀτίταλλον
δεξάμενοι Ῥείας […]
(For I am faring to visit the limits of the all-nurturing earth, and Oceanus, from whom the gods are sprung, and mother Tethys, even them that lovingly nursed and cherished me in their halls, when they had taken me from Rhea […])
Helios rises from the deep-flowing Oceanus in the east and at the end of the day sinks back into the Oceanus in the west.
Likely to be the Universe at large, equivalent of Nun