Custody, in general, means the care and keeping of something. It usually refers to physical care and control of that thing. For example, you might say that assets in a trust are in the custody of the trustee or an inmate in a county jail is in the custody of the Sheriff.
When referring to a child, custody means the person who makes decisions for the child and with whom the child resides. When parents separate, decisions must be made about where the child will reside and how major, non-emergency decisions (such as where the child will attend school, his religious upbringing, extracurricular activities and medical care) will be made. In a perfect world, the parents will agree upon custody of their child. However, if they disagree, the court must decide.
The court may award sole custody to one parent or the other parent. This is more likely to happen in cases where the parents disagree frequently and strongly. The parent with sole custody makes all the major, non-emergency decisions for the child and the child resides with that parent. The other parent usually parenting time (visitation in some states) with the child and will still make minor decisions, such as bedtimes when the child is with him or her, and emergency medical decisions, such as when to call 911 if an emergency arises when the child is with him. In cases of abuse or neglect, however, the other parent may have supervised visitation or no visitation.
In other cases, the court may award joint custody. Usually, this means joint legal custody. Joint legal custody means that the parents will make the major, non-emergency decisions jointly. They will consult with one another and, hopefully, agree about the child’s education, medical care, religion and extracurricular activities. If they don’t agree, however, there is usually a plan spelling out how the final decision will be made (e.g., one parent will have final decision-making authority if the parents cannot reach an agreement).
In most cases, a child who is in the joint legal custody of her parents, will typically reside with one parents most of the time. In Georgia, that parent is said to have primary physical custody of the child. Again, the other parent will have parenting time with the child.
In a few cases, usually when parents are able to cooperate with one another and resolve disagreements in a civil manner, they may have joint physical custody. In some states this is referred to as shared physical custody. This means that the child lives with both parents nearly equally. (Thus, if you want the child to reside nearly equally with each parent, you must find away to get alone with the other parent and resolve any disagreements without bitter arguments. Of course, that is only one of several reasons it is better to get along with your child’s other parent.)