A custodial parent is the parent who is given either legal or physical custody of a child after a divorce or separation, according to USLegal. Physical custody determines where a child lives, and legal custody determines which parent makes decisions affecting the welfare of the child.
Custody is determined by a court system and can be awarded to someone other than the biological parent of the child if the biological parents are absent, deceased, deemed unfit, seen as a danger to the child or in prison, explains USLegal. In these cases, custodial rights are often granted to other relatives, such as grandparents, foster parents or, in some cases, orphanages. Joint custody can also be awarded. In a joint-custody agreement both parents have various rights to the child in terms of living arrangements (typically part-time with each parent) and with decisions regarding the welfare of the child.