foster-
/ˈfɒstə(r)/combining form
1- denoting someone that has a specified family connection through fostering rather than birth表示“有领养关系者”：
foster-parent
foster-child.
1.1
- involving or concerned with fostering a child表示“与收养儿童有关的”：
foster care
foster home.
词源
foster-father, foster-mother, foster-child, and foster-brother all date from Old English. Foster-mother has also been used to mean a wet nurse, her husband being foster-father to the child she fed, and a foster-brother or -sister one reared at the same breast.