In graph structures, nodes, also known as vertices, are fundamental components that represent entities within the graph. Each node can be connected to other nodes through edges, which represent relationships or connections between these entities. The arrangement and connections of nodes and edges form the overall structure of the graph.

There are various types of graphs based on the characteristics of nodes and edges. For instance, in an undirected graph, the connections between nodes are bidirectional, meaning that if node A is connected to node B, then B is also connected to A. Conversely, in a directed graph, the connections have a specific direction, indicating a one-way relationship from one node to another ²⁴.

Additionally, nodes can have specific properties or attributes, and their arrangement can lead to different types of connectivity, such as connected graphs, where every node is reachable from any other node, or biconnected graphs, which do not have articulation points ².

If you have more specific questions about nodes or graph structures, feel free to ask!