Guardian

Guardian is a an adult person entrusted with the care of the person or property of a minor, called a ward, who is not the guardian's child. A father or mother is sometimes called the natural guardian of a child, but the term is not official. At common law, a mother had the right of custody of her minor children only if appointed guardian of them by her husband or by the court.  A guardian may be appointed for an adult incompetent or lunatic.