【上位】 someone who takes the place of another (as when things get dangerous or difficult); "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins" 他人の代わりをする人（危険だったり難しかったりする場合など）。
日/英 »
providing or receiving nurture or parental care though not related by blood or legal ties; "foster parent"; "foster child"; "foster home"; "surrogate father" 日/英 »
