Parent Node: In a hierarchy tree, the parent node refers to the node above another node. It is the immediate ancestor or superior of a specific node.
Child Node: In a hierarchy tree, the child node refers to the node below another node. It is the immediate descendant or subordinate of a specific node.
Leaf Node: A leaf node, also known as a terminal node, is a node in a hierarchy tree that does not have any child nodes. It represents the end point or final element in the hierarchy.