Nun is the primordial ocean of Egyptian cosmology, the boundless, dark, motionless deep that existed before anything else, out of which all creation arose. He is less a personal god with myths of his own than the personification of the uncreated state itself: limitless water without light, form or motion, the condition prior to the first act of making. In the creation accounts, it is out of Nun that the first mound of dry land, the benben, rises, and on it the creator god brings the ordered world into being. Crucially, Nun does not disappear once creation has happened.
The Egyptians imagined the flat, ordered world as a bubble of order surrounded on every side, above the sky, below the earth, and at the edges of the world, by the persisting waters of Nun, which the sun must pass through each night and which are always there, pressing against the boundaries of the cosmos. The annual flooding of the Nile was understood as a renewed touch of these fertile primeval waters. In the Hermopolitan tradition Nun and his female counterpart Naunet head the Ogdoad, the eight primordial deities who embody the chaos before creation. Nun is thus both the beginning of things and the ever-present deep that surrounds and could one day reclaim them.