A child nursed or brought up by one not its own mother or father.(noun)
The Century Dictionary (Public Domain)
Use "foster-child" in a sentence
""Anna Regina Langfus was born in Lublin (Poland) to Moshe Szternfinkiel and his wife Maria (née Wajnberg), who also had a son, older than Anna" - Anna was a single child, the boy in question was a poor foster-child."
"In federal audits since 2001 looking at abuse levels, parent turnover, placement, foster-child adoptions and other measures, no state has passed."
"Protestantism from the foster-child of Rome, the PROTEGEE of"