Physical custody is the term assigned to the custodial parent in relation to custody over a minor child. There is a legal requirement for the parent who holds physical custody to provide for the minor child and ensure that the child's needs are met. This is usually followed by an order for child support against the non-custodial parent in order to assist the parent who holds physical custody in providing for the child's needs. Physical custody can be shared in any proportion deemed appropriate by either the parents or the court system. Physical custody is determined by the court under the legal doctrine of the best interest of the child.
Justipedia explains Physical Custody
When parents of a minor child are separated or divorced, the parent with whom the children live full time is said to have physical custody. If a mother has physical custody over a child who has visitation with the other parent, the mother always maintains physical custody even when the child is with the other parent. The parent who maintains physical custody usually receives child support payments from the other parent. If more than one child is involved, there can be individual arrangements for each child. For example, if a divorcing couple has two children, they can each have physical custody over one of their children while the other parent retains physical custody over the other.