Nun - in Egyptian mythology, primeval matter, the first material manifestation of existence, Nun is primarily a cosmic element. He is a creature of the sea on which the earth floats.
Nun was probably first personified in Hermopolis as a male deity. Sometimes, as one of the deities of the Eight, he had the head of a frog. As the oldest of the gods, dating back to the times of chaos, he was nicknamed "the old one" and the father of times. As a personification of cosmic waters, his attribute was the head of a bull.
Nun is the personification of the primeval ocean, i.e. the mass of water that fills the entire universe. It is a symbol of truths that existed before the creation of the world. It was from there that a proto-hill called Atum emerged, which was also the beginning of the world
From Nun arose the creator and first god - Ra (Re). He began to bring order out of chaos and build the world. He created the first pair of deities: Tefnut, the goddess of moisture, and Shu, the god of air.
Translation from Wikipedia