For purposes of this chapter, the term, “grandparent” means (1) the biological or adoptive parent of either parent of the minor child, including (2) a biological grandparent of a child adopted by a stepparent, or another relative of the child, including a stepparent of the minor child's parent, where a substantial relationship exists between the other relative and the child, and visitation means visitation that is supervised or unsupervised depending on the circumstances of every case and as determined by the court.