Sole Custody. In a sole custody situation, visitation refers to that time set aside by the court for the child to be with the non-custodial parent. The custodial parent (the one with the legal decision making authority) is not ordinarily described as having visitation, though, to my mind this is an error. Visitation in a sole custody situation should refer to the time both parents spend with the child.
Joint Custody. In a joint custody situation, visitation just describes the time both parents spend with the child. Each parent has both custody and a visitation arrangement.
In other words, visitation refers to the time spent with the child and has almost nothing to do with who has legal custody of the child. A common error is to assume that a parent can't spend half the available time with the child without having joint custody. It's not true. I know parents who do not have custody of their children but still get one-half of all the days in a year with them.
To make a long story short: custody and visitation are different animals, so don't confuse them.
Next time: Child Support.