In Egyptian mythology, Shu (meaning dryness and he who rises up) is one of the primordial gods, a personification of air, one of the Ennead of Heliopolis. He was created by Atum from his breath, resulting from an act of masturbation or autofellatio in the city of Heliopolis. With his sister, Tefnut (moisture), he was the father of Nut and Geb.