Ra (sometimes spelled Re or Rah -- also Atum) was the sun-god of Heliopolis in ancient Egypt. From the fifth dynasty (ca. 2400 BC) onward he was combined with the Theban god Amon to become the foremost deity of the Egyptian pantheon. He remained paramount for centuries except for a brief suspension during the time of Akhenaten (1350-1334 BC) when direct and exclusive worship of Aten, the sun disk itself, was imposed on the kingdom of Egypt. In later times, he was associated with Heryshaf.
Ra was a self-creating god, fashioning himself from Mehturt, a mound (see Ogdoad) that came from the waters of Nun, or a lotus flower. He also created Shu and Tefnut out of his semen or mucus, Hu and Sia from the blood from his penis and humanity from his tears.
The sun was either the entire body of Ra, or just his eye. In Heliopolis (the capital of his cult), Ra was worshipped as Atum (the setting sun), Re-Harachte (Venus) and Khepri ("the rising sun"). He was later associated with Horus.
Though Ra and Atum ("he who completes or perfects") were the same god, Atum was used in distinctive fashions. He was primarily the symbol of the setting sun and was also a substitute for Ra as the creator of Shu and Tefnut from either masturbatory semen, (perhaps via autofellatio) or mucus. Atum was himself created by Ptah in some mythologies. Atum was the father of Hike.
Hathor and Ra once argued, and she left Egypt. Ra quickly decided he missed her, but she changed into a cat that destroyed any man or god that approached. Thoth, disguised, eventually succeeds in convincing her to return.
The symbol of Ra is the ⊙ (Circle with a point at its centre), see Solar symbol.
See also: Khepri