goddess tefnut: goddess of moisture, moist air, dew and rain in Ancient Egyptian religion. She is the sister and consort of the air god Shu and the mother of Geb and Nut. Tefnut is a daughter of the solar god Ra-Atum. Married to her brother, Shu, she is mother of Nut, the sky and Geb, the earth. Tefnut's grandchildren were Osiris, Isis, Set, Nephthys, and in some versions, Horus the Elder (Heru Wer). She was also a great grandmother of Horus the Younger.