Dictionary.net

The legal authority to make decisions affecting a child's interests (legal custody) and the responsibility of taking care of the child (physical custody). When parents separate or divorce, one of the hardest decisions they have to make is which parent will have custody. The most common arrangement is for one parent to have custody (both physical and legal) while the other parent has a right of visitation. But it is not uncommon for the parents to share legal custody, even though one parent has physical custody. The most uncommon arrangement is for the parents to share both legal and physical custody.