A Hierarchical Tree is a data structure that organizes information in a tree-like format, where each item, or node, has a parent-child relationship. The top node is called the root, and it branches out to various child nodes, which can further have their own children. This structure is useful for representing relationships, such as organizational charts or file systems. In a hierarchical tree, each node can have multiple children but only one parent, creating a clear path from the root to any leaf node. This makes it easy to navigate and manage data, as seen in applications like XML and JSON for data representation.