Nu ( /nuː/; "watery one") or Nun ( /nʌn/ or /nuːn/; "inert one") is the deification of the primordial watery abyss in Egyptian mythology. In the Ogdoad cosmogony, the word nu means "abyss".
The Ancient Egyptians envisaged the oceanic abyss of the Nun as surrounding a bubble in which the sphere of life is encapsulated, representing the deepest mystery of their cosmogony. In Ancient Egyptian creation accounts the original mound of land comes forth from the waters of the Nun. The Nun is the source of all that appears in a differentiated world, encompassing all aspects of divine and earthly existence. In the Ennead cosmogony Nun is perceived as transcendent at the point of creation alongside Atum the creator god.
Nu was shown usually as male but also had aspects that could be represented as female or male. Nunet ( /ˈnuːˌnɛt/; also spelt Naunet) is the female aspect, which is the name Nu with a female gender ending. The male aspect, Nun, is written with a male gender ending. As with the primordial concepts of the Ogdoad, Nu's male aspect was depicted as a frog, or a frog-headed man. In Ancient Egyptian art, Nun also appears as a bearded man, with blue-green skin, representing water. Naunet is represented as a snake or snake-headed woman.
Beginning with the Middle Kingdom Nun is described as "the Father of the Gods" and he is depicted on temple walls throughout the rest of Ancient Egyptian religious history.
The Ogdoad includes with Naunet and Nun, Amaunet and Amun, Hauhet and Heh, and Kauket with Kuk. Like the other Ogdoad deities, Nu did not have temples or any center of worship. Even so, Nu was sometimes represented by a sacred lake, or, as at Abydos, by an underground stream.
In the 12th Hour of the Book of Gates Nu is depicted with upraised arms holding a "solar bark" (or barque, a boat). The boat is occupied by eight deities, with the scarab deity Khepri standing in the middle surrounded by the seven other deities.
During the late period when Egypt became occupied the negative aspect of the Nun (chaos) became the dominant perception, reflecting the forces of disorder that were set loose in the country.