The wife and sister of Osiris is Isis, a four-letter word. Isis was an ancient Egyptian goddess who was the wife and sister of Osiris, the god of the afterlife, the underworld, and rebirth. She was also the mother of Horus, the god of the sky, war, and protection. Isis was one of the most important and powerful deities in the ancient Egyptian pantheon. She was associated with magic, healing, and protection, and was often depicted as a woman wearing a headdress in the shape of a throne.