foster mother
/ˈfɔstər ˌmʌðər/
noun
- A woman who cares for and raises a child that is not her biological or legal adoptive child, usually through a formal arrangement.
- The foster-mother attended all of the child's parent-teacher conferences.
- She became a foster-mother after her own children had grown up.
- As a foster-mother, she provided a stable and loving home for three children.