Definition of "foster-sister" [foster-sister]

• A female child, not a sister, reared with another child by the same person. (noun)

The Century Dictionary (Public Domain)

• "A DAY BEFORE I was to depart to begin my studies at the University of Tiberium, my foster-sister Edmée was nowhere to be found in the manor of Rocaille, but I knew her habits well enough to guess where she had gone, and I rode out in search of her."
• "The castratos then set before them all manner rich meats and they ate, Daulat Khatun feeding her foster-sister by mouthfuls,453 till she was satisfied; when she called for divers kinds of sweetmeats, and when the neutrals brought them, they ate what they would of them and washed their hands."
• "Jinniyah the foster-sister could have come to her and saved her from old maidenhood."