A node may refer to any of the following:
1. In data communication, a node is any active, physical, electronic device attached to a network. These devices are capable of either sending, receiving, or forwarding information; sometimes a combination of the three. Examples of nodes include bridges, switches, hubs, and modems to other computers, printers, and servers. One of the most common forms of a node is a host computer; often referred to as an Internet node.
2. In graph theory, a node is a unit of data on a graph, connected to other nodes by edges. If the graph is "undirected," the edges can be traversed in either direction to arrive at another node. If the graph is "directed," traversal from node to node may happen only in one direction.