The answer to the crossword for the term 'Sister/Wife of Osiris' is ISIS (4 letters). Isis was an ancient Egyptian goddess who was the sister and wife of Osiris, the god of the afterlife, the underworld, and rebirth. She was also the mother of Horus, the god of the sky. Isis was a powerful goddess who was associated with magic, healing, and protection. She was also known as the goddess of motherhood and fertility.