Wet nurse
A wet nurse is the woman who breastfeeds as living as cares for another's child. Wet nurses are employed if the mother dies, or if she is unable or chooses non to nurse the child herself. Wet-nursed children may be invited as "milk-siblings", in addition to in some cultures, the families are linked by a special relationship of milk kinship. Wet-nursing existed in cultures around the world until the invention of reliable formula milk in the 20th century. The practice has submitted a small comeback in the 21st century.