also: フォスター・チャイルド
noun
A child raised by someone other than their biological parents, typically in a formal foster care arrangement.
彼女はフォスターチャイルドを引き取って育てている。
She has taken in a foster child and is raising them.
フォスターチャイルドとして育った経験を
He spoke about his experience growing up as a foster child.