A "Parent Node" refers to a node in a data structure, such as a tree, that has one or more child nodes connected to it. In this context, a node is a fundamental part of the structure that can hold data and links to other nodes. The parent node is crucial for organizing and managing hierarchical data, allowing for efficient data retrieval and manipulation. In a typical tree structure, the topmost node is called the root node, and it serves as the parent node for its immediate child nodes. Each child node can also be a parent node if it has its own children. This relationship helps in representing complex data relationships in a clear and structured manner.